Combi-sensor systems

ABSTRACT

Certain aspects pertain to a combination sensor comprising a set of physical sensors facing different directions proximate a structure, and configured to measure solar radiation in different directions. The combination sensor also comprises a virtual facade-aligned sensor configured to determine a combi-sensor value at a facade of the structure based on solar radiation readings from the set of physical sensors.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefit of U.S. ProvisionalApplication No. 62/057,104, titled “COMBI-SENSOR SYSTEMS,” filed on Sep.29, 2014, which is hereby incorporated by reference in its entirety andfor all purposes.

FIELD

The present disclosure relates to multiple sensor inputs and datahandling related to same, in particular combi-sensor systems and methodsof determining combi-sensor values.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960s, electrochromicdevices, and particularly electrochromic windows, still unfortunatelysuffer various problems and have not begun to realize their fullcommercial potential despite many recent advances in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

SUMMARY

In certain aspects, a combi-sensor system may be used to improve controlof building systems in a structure having fewer physical sensors thanazimuthal facade positions. For example, a combi-sensor system maydetermine a combi-sensor value for a virtual sensor facing outward froma facade (or facet thereof) lacking its own physical sensor. Thecombi-sensor system can determine this combi-sensor value for thisvirtual sensor based on readings taken by two or more physical sensorsfacing different directions installed at the building.

According to certain aspects, a combi-sensor system uses either acombination technique or an interpolation technique to determine thecombi-sensor value. The first technique combines readings from two ormore physical sensors to determine an aggregate value that applies toall facade orientations at that time. The readings can be combinedby: 1) taking the maximum value of the physical sensor readings, 2)taking the average value of the physical sensor readings, or 3) taking asum of the physical sensor readings. The second technique interpolatesreadings from two or more physical sensors to a virtual facade-alignedsensor using a vector algorithm. Combi-sensor systems may use anycombination of the aforementioned three combination methods.

A combi-sensor system generally comprises two or more physical sensorsfacing distinctly different directions (e.g., having azimuthal anglesthat vary by more than about 80 degrees, by more than about 70 degrees,by more than about 60 degrees, by more than about 50 degrees, etc.). Forexample, a combi-sensor system may include three physical sensors facingdistinctly different directions. As another example, a combi-sensorsystem may include four physical sensors facing distinctly differentdirections. Since these physical sensors face different directions, theymeasure solar irradiance values from these distinctly differentdirections. The solar radiation values are typically recorded over time,for example, on a periodic basis over a day. The solar radiationprofiles of the physical sensor values recorded over time sometimes havea shape similar to bell-shaped Gaussian-type curves. When solarradiation profiles from physical sensors facing distinctly differentazimuthal angles are overlaid, the curves are somewhat similar in shapeto each other and/or shifted time-wise from each other. The maximums,averages or sums of the profiles may be used to determine values fromfacades or directions where there are no physical sensors. In this way,the complexity of having many sensors facing in many directions isavoided. Simpler physical systems are realized, i.e. less physicalsensors, while retaining the input as if one had many more physicalsensors.

In some examples of combi-sensor systems described herein, the physicalsensors are facing directions that are approximately orthogonal to eachother. For example, a combi-sensor system may comprise four physicalsensors facing approximately orthogonal directions (e.g., approximatelyin the directions of North (N), South (S), East (E) and West (W)). Inother examples, the combi-sensor system includes three physical sensorsinstalled on a building. In some cases, a comb-sensor system comprisesthree physical sensors that are facing approximately orthogonaldirections. In certain examples where the building is located in anorthern latitude, the three orthogonally-directed physical sensors faceapproximately W, E, and S. In certain examples where the building islocated at a southern latitude, the three orthogonally-directed physicalsensors face approximately W, E, and N.

In certain embodiments, a combi-sensor value may be used as input tocontrol a building system. For example, a combi-sensor value may be usedas input to a control system that determines tinting decisions forelectrochromic (EC) window(s) or in a building and controls power to thewindow(s) to implement the tinting decisions. An example of such acontrol system is described in Section X. This control system usesoperations of what are described as “Modules A, B, and C” ofIntelligence™ EC control software to determine the tint decisions(Intelligence™ is commercially available from View, Inc. of Milpitas,Calif.). In one embodiment, this control system uses Module A todetermine a tint level that provides occupant comfort from glare to aworkspace from sunlight penetrating a room and uses Module B to increasethe tint level based on clear sky predictions of solar irradiance atthat time of the day. Module C may then use irradiance readings taken byone or more sensors (either physical or virtual) to override the tintlevel from Modules A and B, or not. For example, a combi-sensor valuemay be used as input to Module C. Module C may override the tint levelfrom Modules A and B to make the tint level lighter based on thecombi-sensor value. That is, if the combi-sensor value is higher thanthe clear sky irradiance level used in Modules A and B, then Module Cwill not override Modules A and B and will ignore the highercombi-sensor irradiance value. If the combi-sensor value is lower thanthe clear sky irradiance level used in Modules A and B, then Module Cwill override Modules A and B. For illustration purposes, manyembodiments are described herein with reference to input to the Modulesof this particular control system, it would be understood however thatthe combi-sensor system can be used to generate combi-sensor value(s) asinput for other control systems that rely on irradiance measurements aswell, for example other smart window control algorithms or controlalgorithms for other systems such as HVAC, building management systems(BMS), solar tracking systems, etc. Embodiments disclosed are useful fordetermining solar irradiance on surfaces that do not have a physicalsensor associated with the surface by using a “virtual sensor” whichderives output from readings from physical sensors in other locations.In one embodiment a combi-sensor system includes hardware and software,while other aspects are embodied in software and/or methods alone, i.e.without physical components.

In certain embodiments, a combi-sensor system comprises a set of atleast three azimuthally distinct physical sensors (i.e. directed todifferent azimuth angles). In some aspects, a combi-sensor systemcomprises four azimuthally distinct physical sensors. In some aspects, acombi-sensor system comprises three azimuthally distinct physicalsensors. In some cases, these azimuthally distinct physical sensors areoriented in approximately orthogonal directions. The physical sensorsare typically, though not necessarily, located on facades of a building.The combi-sensor system uses these physical sensors to determine solarirradiation for other facades not having physical sensors thereon. Inone embodiment, the combi-sensor system comprises threeorthogonally-directed physical sensors directed to North, 90 degreesfrom North and 270 degrees from North. In one embodiment, thecombi-sensor system comprises three orthogonally-directed physicalsensors directed to 90 degrees from North, 180 degrees from North, and270 degrees from North. Combi-sensor systems may include more sensors,e.g. between two and twenty sensors, or between two and fifteen sensors,or between two and ten sensors, or between two and five sensors,depending on for example, how many facets and/or levels a structure has,the level of granularity and precision one requires the output to be,and the like.

Certain aspects pertain to a combination sensor comprising a set ofphysical sensors facing different directions proximate a structure(e.g., a building). The physical sensors are configured to measure solarradiation in different directions. The combination sensor furthercomprising a virtual facade-aligned sensor configured to determine acombi-sensor value at a facade of the structure based on solar radiationreadings from the set of physical sensors.

Certain aspects pertain to methods comprising determining solarradiation readings taken by a set of physical sensors and determining acombi-sensor value of a virtual facade-aligned sensor based on the solarradiation readings taken by the set of physical sensors. In some cases,the set of physical sensors are facing different directions proximate astructure (e.g., a building) and are configured to measure solarradiation in different directions.

These and other features and embodiments will be described in moredetail below with reference to the drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a schematic drawing of a plan view of a structure whichincludes a multi-faceted rotunda, according to an embodiment.

FIG. 1B is a drawing of a compass including the directions of some ofthe facets of the multi-faceted rotunda structure shown in FIG. 1A,according to an embodiment.

FIGS. 2A-2C are three graphs with solar radiation profiles for azimuthangles varying from 0-350 degrees at 10 degree increments during a dayin January, April, and July respectively, according to an embodiment.

FIGS. 3A-3B are two graphs with solar radiation profiles for azimuthangles of 140 degrees from North, 90 degrees from North or East-facing,180 degrees from North or South-facing, according to an embodiment.

FIG. 4 is a schematic diagram of a combi-sensor system at amulti-faceted building and building control systems, according toembodiments.

FIGS. 5A and 5B depict diagrams showing the solar radiation exposure atdifferent times of day for geographical locations in the southernhemisphere and northern hemisphere respectively, according toembodiments.

FIG. 6A depicts three graphs of solar radiation profiles based on actualreadings from the East-facing sensor, the South-facing sensor, and theWest-facing sensor of the combi-sensor system installed at the building,according to an embodiment.

FIG. 6B depicts graphs from FIG. 6A with the addition of a solarradiation profile (dotted line) in the direction of a facade at 150degrees from North—SE facing facade (60 degrees off East and 30 degreesoff South), according to an embodiment.

FIG. 7A is a graph illustrating an example of an aggregate curve(shaded) of combi-sensor values determined from sunrise to sunset usingthe maximum value method for a combi-sensor system comprising threeorthogonally-directed sensors (sensor 1, sensor 2, and sensor 3),according to an embodiment.

FIG. 7B is graph illustrating an example of an aggregate curve (dottedline) of combi-sensor values determined using the maximum value methodover the Summer Solstice day, according to embodiments.

FIG. 7C depicts a graph illustrating an example of an envelope (shadedarea) of an aggregate curve of combi-sensor values, over a day,determined using the maximum value method, according to an embodiment.

FIG. 8A depicts a graph including a solar radiation profile (dottedline) based on clear sky predictions of solar radiation on a sunny dayon a facade-aligned sensor, according to an embodiment.

FIG. 8B depicts a graph that includes an aggregate curve of combi-sensorvalues using the additive method, according to an embodiment.

FIG. 8C depicts a graph that includes an aggregate curve of combi-sensorvalues using the maximum value method, according to an embodiment.

FIG. 8D depicts a graph that includes an aggregate curve of combi-sensorvalues using the average value method, according to an embodiment.

FIG. 9 depicts a graph including theoretical solar radiation readings(dotted line) and simulated solar radiation readings on a cloudy dayfrom a facade-aligned sensor, according to an embodiment.

FIG. 10A depicts a graph that includes an aggregate curve ofcombi-sensor values using the maximum value method, according to anembodiment.

FIG. 10B depicts a graph that includes an aggregate curve ofcombi-sensor values using the additive value method, according to anembodiment.

FIG. 10C depicts a graph that includes an aggregate curve ofcombi-sensor values using the average value method, according to anembodiment.

FIG. 11 is an example of a solar radiation curve of an interpolatedvirtual facade-aligned sensor as interpolated using a vector algorithmfrom readings taken by a first physical sensor (sensor 1) and readingstaken by a second physical sensor (sensor 2) of a combi-sensor system,according to an embodiment.

FIG. 12A shows an example of the impact of out-of-phase sensors whichare trailing the facade, according to embodiments.

FIG. 12B shows an example of the impact of out-of-phase sensors whichare leading the facade, according to embodiments.

FIG. 12C include a phase diagram for physical sensors leading the facadeduring the winter solstice times, according to embodiments.

FIG. 12D is a phase diagram illustrating the yearly maximum impact ofout-of-phase sensors leading the facade, according to embodiments.

FIG. 12E is a phase diagram illustrating the yearly maximum impact ofout-of-phase sensors trailing the facade, according to embodiments.

FIG. 13A is a graph with the theoretical solar radiation profiles fordifferent façade orientations (every 10 degrees) during summer solsticeand with the combi-sensor values for a combi-sensor system, according toan embodiment.

FIG. 13B is a graph with the theoretical solar radiation profiles fordifferent façade orientations (every 10 degrees) during winter solsticeand with the combi-sensor values for the combi-sensor system of FIG.13A, according to an embodiment.

FIG. 14A shows a graph having two aggregate curves of combi-sensorvalues based on readings from a ring sensor comprising fourequally-spaced physical sensors separated by 90 degrees, according to anembodiment.

FIGS. 14B-14E are graphs associated with different ring sensorarrangements comprising four (4) physical sensors, eight (8) physicalsensors, twelve (12) physical sensors, and eighteen (18) physicalsensors respectively, according to embodiments.

FIG. 14F is a chart of the maximum difference (delta) between the firstand second aggregate curves from FIGS. 14B-14E for ring sensors havingfour (4), eight (8), twelve (12) and eighteen (18) equally spacedphysical sensors.

FIG. 15 depicts a simplified block diagram of components of a windowcontroller.

FIGS. 16A-16C include diagrams depicting information collected by eachof three Modules A, B, and C of an exemplary control logic, according todisclosed embodiments.

FIG. 17 is a flowchart showing some steps of predictive control logicfor a method of controlling one or more electrochromic windows in abuilding, according to disclosed embodiments.

FIG. 18 is a flowchart showing a particular implementation of a portionof the control logic shown in FIG. 17.

FIG. 19 is a flowchart showing details of Module A according todisclosed embodiments.

FIG. 20 is an example of an occupancy lookup table according todisclosed embodiments.

FIG. 21A depicts a schematic diagram of a room including anelectrochromic window with a space type based on a Desk 1 located nearthe window, according to disclosed embodiments.

FIG. 21B depicts a schematic diagram of a room including anelectrochromic window with a space type based on a Desk 2 located faraway from the window, according to disclosed embodiments.

FIG. 22 is a flowchart showing details of Module B according todisclosed embodiments.

FIG. 23 is a flowchart showing details of Module C according todisclosed embodiments.

FIG. 24 is a diagram showing another implementation of a portion of thecontrol logic shown in FIG. 17.

FIG. 25 is a block diagram depicting predictive control logic for amethod of controlling the transitioning of tint levels of one or moretintable windows (e.g., electrochromic windows) in a building.

FIG. 26A is a flowchart showing a particular implementation of a portionof the control logic shown in FIG. 17.

FIG. 26B is a graph of illumination readings during a day that is cloudyearly in the day and then sunny later in the day and the correspondingupper and lower limits.

FIG. 27A is a flowchart of a control method that uses box car values tomake tinting decisions, according to embodiments.

FIG. 27B depicts a room having a desk and the critical angle of the roomwithin which the sun is shining onto an occupant sitting at the desk

FIG. 28A depicts two graphs associated with sensor readings during aregular day and the associated determined tint states determined of acontrol method using box car filters, according to embodiments.

FIG. 28B depicts two graphs associated with sensor readings during acloud day with intermittent spikes and the associated determined tintstates determined of a control method using box car filters, accordingto embodiments.

FIG. 29A is a flowchart of a control method that uses box car values tomake tinting decisions, according to embodiments.

FIG. 29B is a plot of illumination values including sensor readings,short box car values, and long box car values determined during time, t,during a day.

FIG. 30A is a flowchart of a control method that uses box car values tomake tinting decisions, according to embodiments.

FIG. 30B is a plot of illumination values including sensor readings,short box car values, and long box car values determined during time, t,during a day.

DETAILED DESCRIPTION I. Introduction

Buildings and other structures sometimes have sensors installed tomeasure solar radiation such as photosensors, photometers, radiometers,ultraviolet sensors and the like. The measurements taken by thesesensors can be used as input to control building systems (e.g., HVAC,electrochromic window systems, for example, to maintain a comfortableenvironment for its occupants or maximize power generation, and solartracking, for example, to maintain a comfortable environment for itsoccupants or maximize power generation, etc. For structures having smartwindows that tint on demand, for example, ideally, a structure wouldhave a separate sensor installed on each wall at each floor (i.e. thereis at least one sensor facing the direction of every facet of thestructure). The number and locations of sensors installed on astructure, however, are usually limited. For example, the number andlocation of sensors visible from outside the building may be restrictedfor aesthetic reasons. Also, it may not be practical to have a sensor onevery facet of a multi-faceted structure. Moreover, sensors installed ona structure can be become inoperable or malfunction making sensor dataunavailable. Also, a sensor could become misaligned from the planneddirection. Using data from a sensor that is substantially misalignedfrom the facet direction could result in improper or fluctuating controlof the building systems that may be noticeable and/or uncomfortable tooccupants of the building. For these reasons, sensor data is generallynot available for every facet of the structure.

FIGS. 1A-1B are illustrations associated with an example of a building10 with a multi-faceted rotunda 100, according to embodiments. FIG. 1Ais a schematic drawing of a plan view of the multi-faceted rotunda 100.A directional arrow is shown pointing due North. The multi-facetedrotunda 100 comprises three physical sensors 110, 112, and 114 (e.g.,photosensors) installed at directions denoted by solid arrows. The threesensors may be, for example, at the roofline of structure 100 to providereliable readings and not be blocked by physical obstructions fromneighboring structures. The first physical sensor 2110 faces thedirection of 264 degrees from North, which is approximately West-facing.The second physical sensor 112 faces the direction of 180 degrees fromNorth, which is South-facing. The third physical sensor 114 faces thedirection of 100 degrees from North, which is nearly East facing. Thedirections of the three physical sensors 110, 112, and 114 are or areabout West-facing, South-facing, and East facing, respectively. Thefirst and third physical sensors 110 and 114 are installed on facetswith windows. Many of the facets of the structure 100 are not alignedwith the direction of one of the physical sensors 110, 112, and 114. Forexample, physical sensors are not installed on other facets 121, 122,123, 124, and 125 of the building that also have windows. Facet 122 isfacing the direction (denoted by dotted arrow) of 180 degrees fromNorth, which is aligned with the direction of the second (South facing)physical sensor 112. The other facets 121, 123, 124, and 125, however,face directions of 242°, 115°, 140°, and 60° respectively (denoted bydotted arrows) that are not aligned with any of the directions of thethree physical sensors 110, 112, and 114 installed on the multi-facetedrotunda structure 100. A wall switch 120 is located on an inner wall ofthe multi-faceted rotunda structure 100. Although many embodiments aredescribed herein with respect to windows, one skilled in the art wouldunderstand that doors and other orifices of the structure would alsoapply.

FIG. 1B is a drawing of a compass 130 including the directions of someof the facets of the multi-faceted rotunda structure 100 shown in FIG.1A. The compass 130 includes solid arrows denoting the directions of thefacets with physical sensors 110, 112 and 114 i.e. 264°, 180° and 100°,respectively. Compass 130 also includes dotted arrows denotingdirections of facets facing directions that are not in alignment withany of the directions of the three physical sensors 110, 112 and 114.For example, compass 130 includes dotted arrows denoting the directionsof the facets 121, 123, 124 and 125 (242°, 115°, 140° and 60°) that arenot in alignment with any of the directions of the three physicalsensors 110, 112, and 114. The compass 130 also includes dotted arrowsdenoting other directions (225°, 130°, 120° and 24°) of facets notaligned in alignment with any of the directions of the three physicalsensors 110, 112, and 114. Although not shown by directional arrows,other facets are not aligned to the directions of the three physicalsensors 110, 112, and 114.

FIGS. 2A-2C depict three graphs of multiple solar radiation profiles(solar radiation in W/m² v. time) for solar radiation values during aday in January, April, and July respectively, according to anembodiment. Each graph includes multiple solar radiation profiles forazimuth angles varying by 10 degrees from 0-350 degrees. The solarradiation profiles are associated with the geographical location (i.e.longitude and latitude) of building with the rotunda structure 100 shownin FIG. 1A. Each solar radiation profile is the solar radiation profilesis the solar radiation over time between sunrise and sunset during a dayat that time of the year.

FIGS. 3A-3B depict two graphs of solar radiation profiles for theazimuth angles of 140 degrees from North, 90 degrees from North orEast-facing, 180 degrees from North or South-facing. The solar radiationprofiles are associated with the geographical location of building 10with the rotunda 100 shown in FIG. 1A. The solar radiation profiles inFIG. 3A is over a day in January. The solar radiation profiles in FIG.3B is over a day in July. As shown in FIG. 3A, the solar radiationprofile (solid line) at the azimuth angle of 140 degrees from North ismore similar to the South-facing profile (dotted line) than theEast-facing profile in January. As shown in FIG. 3B, the solar radiationprofile (solid line) at the azimuth angle of 140 degrees from North ismore similar to the East-facing profile (dotted line) than theSouth-facing profile in July.

As mentioned above, physical sensors can be misaligned from thedirection to which they are intended to be configured (e.g., installed)to measure solar radiation. This misalignment can result in the sensorstaking solar radiation measurements (also called “lux” in some instancesherein) that do not correspond to the amount of solar radiation thatimpinges the façade from that direction. The measurements correspond tothe misaligned direction. This misalignment can result in the sensorproviding inaccurate data as input to the control system such as awindow controller electronically tinting windows or shading systems onthat façade. Combi-sensor systems can account for misalignment andprovide accurate sensor data, as well as allow for less physical sensorsin a given installation while retaining a data input approximating thatwhich would be available with more physical sensors.

II. Introduction to Combi-Sensor Systems

In certain aspects, a combi-sensor system may be used to improve controlof building systems in a structure having fewer physical sensors thanazimuthal facade positions and/or fewer physical sensors than verticalfloors in the building. For example, a combi-sensor system may determinea combi-sensor value for a “virtual” sensor facing outward from a facade(or facet thereof) lacking its own physical sensor. The combi-sensorsystem can determine this combi-sensor value for this virtual sensorbased on readings taken by two or more physical sensors facing differentdirections installed at the building.

According to certain aspects, a combi-sensor system uses either acombination technique or an interpolation technique to determine thecombi-sensor value. The first technique combines readings from two ormore physical sensors to determine an aggregate value that applies toall facade orientations at that time. The readings can be combinedby: 1) taking the maximum value of the physical sensor readings, 2)taking the average value of the physical sensor readings, or 3) taking asum of the physical sensor readings. The second technique interpolatesreadings from two or more physical sensors to a virtual facade-alignedsensor using a vector algorithm.

A combi-sensor system generally comprises two or more physical sensorsin different locations, azimuthally (as observed in a plane parallel tothe floors of a building or, for example, located at different verticallocations, e.g. floors, of a building). For azimuthally distinctphysical sensors, for example, physical sensors facing distinctlydifferent directions (e.g., having azimuthal angles that vary by morethan about 80 degrees, by more than about 70 degrees, by more than about60 degrees, by more than about 50 degrees, etc.). For example, acombi-sensor system may include three physical sensors facing distinctlydifferent directions. As another example, a combi-sensor system mayinclude four physical sensors facing distinctly different directions.Since these physical sensors face different directions, they measuresolar irradiance values from these distinctly different directions. Thesolar radiation values are typically recorded over time, for example, ona periodic basis over a day. The solar radiation profiles of thephysical sensor values recorded over time sometimes have a shape similarto bell-shaped Gaussian-type curves. When solar radiation profiles fromphysical sensors facing distinctly different azimuthal angles areoverlaid, the curves are somewhat similar in shape to each other and/orshifted time-wise from each other. For example, these curve overlays canbe used to determine or estimate solar irradiance occurring on facadeswith azimuthal orientations different from those facades bearingphysical sensors.

In some examples of combi-sensor systems described herein, the physicalsensors are facing directions that are approximately orthogonal to eachother. For example, a combi-sensor system may comprise four physicalsensors facing approximately orthogonal directions (e.g., approximatelyin the directions of North (N), South (S), East (E) and West (W)). Inother examples, the combi-sensor system includes three physical sensorsinstalled on a building. In some cases, a comb-sensor system comprisesthree physical sensors that are facing approximately orthogonaldirections. In certain examples where the building is located in anorthern latitude, the three orthogonally-directed physical sensors faceapproximately W, E, and S. In certain examples where the building islocated at a southern latitude, the three orthogonally-directed physicalsensors face approximately W, E, and N.

As described herein, a physical sensor may be considered to faceapproximately in a particular direction if it is, for example, within 5degrees of the direction, within 2 degrees of the direction, within 3degrees of the direction, in a range of 1-10 degrees of the direction,in a range of 5-15 degrees of the direction, and/or in a range of 1-5degrees of the direction.

In certain embodiments, a combi-sensor value may be used as input tocontrol a building system. For example, a combi-sensor value may be usedas input to a control system that determines tinting decisions forelectrochromic (EC) window(s) or in a building and controls power to thewindow(s) to implement the tinting decisions. An example of such acontrol system is described in Section X. This control system usesoperations of Modules A, B, and C to determine the tint decisions. Inone embodiment, this control system uses Module A to determine a tintlevel that provides occupant comfort from glare to a workspace fromsunlight penetrating a room and uses Module B to increase the tint levelbased on clear sky predictions of solar irradiance at that time of theday. Module C may then use irradiance readings taken by one or moresensors (either physical or virtual) to override the tint level fromModules A and B. For example, a combi-sensor value may be used as inputto Module C. Module C may override the tint level from Modules A and Bto make the tint level lighter based on the combi-sensor value. That is,if the combi-sensor value is higher than the clear sky irradiance levelused in Modules A and B, then Module C will not override Modules A and Band will ignore the higher combi-sensor irradiance value. If thecombi-sensor value is lower than the clear sky irradiance level used inModules A and B, then Module C will override Modules A and B. Forillustration purposes, many embodiments are described herein withreference to input to the Modules of this control system, it would beunderstood however that the combi-sensor system can be used to generatecombi-sensor value(s) as input for other systems as well.

III. Examples of Combi-Sensor Systems

In certain embodiments, a combi-sensor system comprises a set of atleast three azimuthally distinct physical sensors (i.e. directed todifferent azimuth angles). In some aspects, a combi-sensor systemcomprises four azimuthally distinct physical sensors. In some aspects, acombi-sensor system comprises three azimuthally distinct physicalsensors. In some cases, these azimuthally distinct physical sensors areoriented in approximately orthogonal directions. That is, each of theseorthogonally-directed sensors is directed at an azimuth angle that isapproximately 90 degrees (e.g., 90 degrees±5 degrees, 90 degrees±2degrees, 90 degrees±1 degrees) from the azimuth angle of at least oneother physical sensor. In some examples of systems with fourorthogonally-directed sensors, the physical sensors may directed to faceapproximately N, E, S, and W (e.g., ±5 degrees from North, ±5 degreesfrom East, ±5 degrees from South, ±5 degrees from West; +3 degrees fromN, E, S, W; and +2 degrees from N, E, S, W; +1 degrees from N, E, S, W).In one embodiment, the system comprises four orthogonally-directedphysical sensors directed to North, 90 degrees from North, 180 degreesfrom North, and 270 degrees from North.

FIG. 4 is a schematic diagram of a combi-sensor system 140 at amulti-faceted building and building control systems, according toembodiments. The combi-sensor system 140 comprises four physical sensors142, 144, 146, and 148. The multi-faceted structure is octagonal, havinga first façade 152, a second façade 154, a third façade 156, a fourthfaçade 158, and fifth façade 160, a sixth façade 162, a seventh façade164 and an eighth façade 166. The first physical sensor 142 is directedto 0 degrees from North (North), which is the direction normal to thefirst facade 152. The second physical sensor 144 is located on the thirdfaçade 156 and is directed to 90 degrees from North (East), which is inthe normal direction of the third facade 156. The third physical sensor146 is located on the fifth facade 160 and is directed to 180 degreesfrom North (South), which is the normal direction of the fifth facade160. The fourth physical sensor 148 is located on the seventh facade 164and is directed to 270 degrees from North (West), which is the normaldirection to the seventh facade 164.

In FIG. 4, combi-sensor system 140 further comprises a first virtualsensor 172 in a direction normal to the second façade 154 and a secondvirtual sensor 174 in a direction normal to the fourth façade 158. Inaddition, the combi-sensor system 140 comprises a third virtual sensor176 in the direction normal to the sixth façade 162 and a fourth virtualsensor 178 in the direction normal to the eighth façade 166. Althoughthe structure in FIG. 4 is shown having eight facades on a single floorof a structure, the combi-sensor system 140 can be used with a structurehaving more or fewer facades/facets and/or a structure having multiplefloors. Although many of the sensors are shown on the outside offacades, a sensor can be at another location from the façade whileoriented (pointed) in the direction of the corresponding façade. Forexample, first physical sensor 142 is not located on the first façade152, but is in a normal direction to the first façade 152.

In FIG. 4, the physical sensors are in electrical communication (notshown) with the building management system (BMS) 2710 to send andreceive data such as sensor data. The BMS 2710 may be a component of thecombi-sensor system 140, or may be a separate component. The BMS 2710 isin communication with a fire system 2720, an elevators system 2730, apower system 2740, a security system 2750, an HVAC system 2760, and alighting system 2770. In this example, the BMS 2710 is receiving sensordata from the physical sensors 142, 144, 146, and 148 and sendingcontrol instructions to the windows of the structure. Details of otherpossible components of combi-sensor system 140 are described in SectionX.

In certain aspects, the combi-sensor system 140 is in communication withone or more window controllers for controlling EC windows in themultifaceted structure.

FIGS. 5A and 5B are diagrams showing the solar radiation exposure atdifferent times of day for geographical locations in the southernhemisphere and northern hemisphere respectively. As shown in FIGS. 5Aand 5B, North is actually precisely opposite of south however exposureto the north is covered by the combination of East and West and viceversa in the southern hemisphere.

For buildings geographically located in the Northern hemisphere, thenorth facing facades are only exposed to morning and evening sun for abrief time (and only in summer months) which would be covered by an eastand west facing physical sensor combined. In these cases, the northernexposure's radiant component is less impactful and, in certain cases,may be omitted from a combi-sensor system's physical sensors. In oneexample of a building geographically located in a northern latitude, acombi-sensor system comprises three orthogonally-directed physicalsensors facing approximately W, E, and S.

For buildings geographically located in the Southern hemisphere, thesouth facing facades are only exposed to morning and evening sun for abrief time (and only in summer months) which would be covered by an eastand west facing physical sensor. In these cases, the southern exposure'sradiant component is less impactful and, in certain cases, may beomitted from the combi-sensor system's physical sensors. In one exampleof a building geographically located in a southern latitude, acombi-sensor system comprises three orthogonally-directed physicalsensors facing approximately W, E, and N.

In one embodiment, a combi-sensor system comprises threeorthogonally-directed physical sensors installed at a building insouthern California, which is in the Northern Hemisphere. The threeorthogonally-directed physical sensors comprise an East-facing sensor at90 degrees from North, a South-facing sensor at 180 degrees from North,and a West-facing sensor at 270 degrees from North. FIG. 6A providesthree graphs of solar radiation profiles (solar radiation W/m² vs timeof day) based on actual readings taken by the East-facing sensor, theSouth-facing sensor, and the West-facing sensor of the combi-sensorsystem associated with the building. As shown, the East, West, and Southfacing facades experience different amounts of solar radiation at thesame time of day. The arrows (at morning, afternoon, and evening) showthat the facades have different profiles.

Although the hardware elements, for example photosensors, may beinstalled at a building, algorithms and associated computing hardwaremay be located elsewhere, e.g. at a processing center or at the samebuilding at the photosensors. Although typically the physical sensorsare installed on the building façade, they may also be installedproximate the building and oriented as they would be if on the façade ofthe building, or both having some sensors on the building and some noton the building. Also, for example where two or more buildings are inthe same vicinity and have similar orientations and configurations, thephysical sensors may be on only one such building and the combi-sensorsystem serve the needs of control algorithms for window tintingfunctions of other buildings in the vicinity. In another example, wheretwo or more buildings are in the same vicinity and have similarorientations and configurations, the physical sensors may be dispersedon different buildings while serving a single combi-sensor system andone or more building's window tinting control algorithms. Thus a groupof sensors on a single building and/or a network of sensors in disparatelocations can be part of a combi-sensor system that serves one or morebuildings. Where weather and sun patterns are similar over largergeographical areas, a combi-sensor system may serve several buildings inthat geographical area.

FIG. 6B shows the same profiles (solid lines) from FIG. 6A with theaddition of solar radiation profiles (dotted lines) in the direction ofa facade at 150 degrees from North-Southeast (SE) facing facade (60degrees off East and 30 degrees off South). If only actual irradiancereadings from the physical sensors on the East, South and/or West facingfacades were used as input to an electrochromic window switchingalgorithm, problems could arise when determining tint values for, e.g.,the southeast (SE) façade. For example, in the morning, if either theSouth or West-facing sensors were used as input for the SE facade toModule C, they would cause Module C to override the tint level fromModules A/B lowering the tint level to too low a level, because theSouth or West facing sensors do not read much solar intensity at thattime. This would cause a potential glare scenario since the irradiancelevel of the SE facade is higher, thus the readings from S and W sensorsat that time would send a “false” reading. Thus, the highest irradiancevalue of the East facing facade would be a better value to use in themorning as a surrogate for an irradiance reading at the SE facade. Inthe afternoon, the East-facing facade is getting much less solarexposure and Module C would clear (override Module A and B tint values)if using the East-facing facade sensor value alone while the SE facadecould still be exposed to significant radiation (because the S façade isexperiencing solar irradiation sufficient for glare). Thus, the highestirradiance value of the South facing facade would a better value to usein the afternoon as a surrogate for an irradiance reading at the SEfacade. In another example, in the evening, if the South facing facadeirradiance value was used as a surrogate for the south west (SW) façade,Module C of the control system for tinting/clearing electrochromic (EC)windows discussed in Section X would override the tint value set byModules A and B and clear the glass. This also would expose the SWfacade to uncomfortably high solar radiation, because the West façade isexposed to high solar irradiance at that time (and thus the SW façade).Thus, the West-facing facade with the highest irradiance value is moreappropriate as an irradiance input for evening on the SW facade. SinceModule C can only lighten, by overriding tint decisions from Modules Aand B, the evening times are irrelevant for the SE facade. Module A andB would have already maximally cleared the window in the early evening.Combi-sensor systems can calculate expected solar exposure at facadeshaving no physical sensors and thereby ensure that tint overridecommands are given appropriately for windows on particular facades of abuilding.

IV. Vertically Sparse Physical Sensors

Just as a combi-sensor system can be used to determine virtual sensorvalues by using physical sensor values about a azimuthal spanhorizontally, so can a combi-sensor system determine virtual sensorvalues at vertical levels (e.g., floors, or spaced apart horizontallyand oriented the same direction) without physical sensors i.e. in astructure having vertically sparse physical sensors. In certain aspects,a combi-sensor system determines a combi-sensor value at intermediatelevels between levels with physical sensors or at other levels withoutphysical sensors. For example, certain lower floors of a building may beshaded by neighboring buildings, while upper floors are not. Acombi-sensor system can be used to determine combi-sensor light valuesfor virtual sensors on those lower floors that do not have physicalsensors. In other aspects, a combi-sensor system can determine acombi-sensor value based on readings from multiple vertically separatedphysical sensors on a single facade. The values from the individualvertically separated physical sensors could be combined in the same wayas the values from azimuthally separated sensors as described in SectionV below. The combi-sensor value may be used as a combined output intoModule C for all of the vertical sections on the facade, for example.

V. Techniques for Determining Combi-Sensor Values for Virtual Sensorsnot in Phase with Physical Sensors

There are two main techniques for determining a combi-sensor value for avirtual facade-aligned sensor. The first technique combines readingsfrom two or more physical sensors to determine an aggregate combi-sensorvalue that can be used for all orientations. The second techniqueinterpolates readings from two or more physical sensors to the virtualfacade-aligned sensor using a vector algorithm.

Technique 1.

The first technique combines readings at any given time from three ormore physical sensors facing azimuthally distinct directions todetermine a combi-sensor value. This combi-sensor value applies to allfacade orientations for the given time. An aggregate envelope is an areaenclosed by the curve defined by the aggregate combi-sensor values forthat day. The aggregate value is determined by one of the followingmethods: 1) determining a maximum value of the physical sensor values,2) averaging the physical sensor values, or 3) summing the physicalsensor values.

Method 1—Maximum Value Method

The first method determines a combi-sensor value, at each sample time,which is the maximum value of all the readings taken by the three ormore physical sensors. The determined maximum values generate anaggregate envelope that contains the solar radiation profiles from allpossible facade orientations for the day. That is, all facades areexperiencing a solar radiation at or lower than the maximum sensorvalue. This method retains the magnitude of output of a single physicalsensor since each maximum value is of a single sensor at each sampletime. Since the magnitude of the single physical sensor is retained,this allows for the combination of sensors in legacy installations orcombination of combi-sensors and single sensors. That is, with thismethod, it does not matter how many sensors are added or removed fromthe combi-sensor system, the aggregate envelope should remain the sameand thus, the magnitudes of these maximum values remain accurate.

FIG. 7A is a graph illustrating an example of an aggregate curve(shaded) 180 of combi-sensor irradiance values determined from sunriseto sunset using the maximum value method for a combi-sensor systemcomprising three orthogonally-directed physical sensors (sensor 1,sensor 2, and sensor 3), according to an embodiment. The graph alsoincludes three solar radiation profiles 182, 184, and 186 from sensor 1,sensor 2, and sensor 3 respectively on a day of the year. As shown, theaggregate curve 180 contains the solar radiation profiles 182, 184, and186. The aggregate combi-sensor values from the aggregate curve 180 canbe used as input into a building control system that use irradiancevalues in directions that are not aligned with physical sensors. Thecombi-sensor values can be used as surrogate values for actualirradiance readings. The combi-sensor values at a given time of the daycan be used as surrogate irradiance readings in various directions at ornearby the location of the combi-sensor system installation. Forexample, the combi-sensor values can be used as input to a controlsystem that determines tint states for electrochromic windows asdiscussed in Section X.

FIG. 7B is graph illustrating an example of an aggregate curve 188(dotted line) of combi-sensor values determined using the maximum valuemethod over the Summer Solstice day, according to embodiments. Theaggregate curve is based on taking the maximum values of predicted clearsky solar radiation profiles for the three orientations East, South, andWest. The graph also includes overlapping clear sky predicted solarradiation profiles (multiple solid lines) for every 10 degrees ofazimuth angle orientations ranging from 0 (360) degrees to 350 degreesof a structure. As shown, the aggregate curve envelope will include themaximum values of all possible facade orientations for the day. That is,the combi-sensor value at each sample time will be greater or equal tothe readings at all possible facades.

FIG. 7C is a graph illustrating an example of an envelope (shaded area)of an aggregate curve 190 of combi-sensor values, over a day, determinedusing the maximum value method, according to an embodiment. In theaggregate curve 190, the combi-sensor values are based on the maximumsolar radiation measured by the combined East-facing sensor,South-facing sensor, and West-facing sensor of a structure. The graphalso includes a theoretical aggregate curve 192 of combi-sensor valuesgenerated using the maximum value method by determining the maximumvalue of the combined predicted clear sky radiation values from theEast-facing sensor, South-facing sensor, and West-facing sensor. Thegraph also includes a theoretical clear sky solar radiation profile 194of a façade facing 150 degrees of North (60 degrees off East) i.e. SEfacing facade. The aggregate curve 192 is the theoretical combined clearsky maximum irradiance for all modeled facades for comparison to thetheoretical solar radiation profile 194 of the SE facade to show thatthe theoretical radiation of the SE facade falls within the envelope ofall maximum theoretical values in aggregate curve 192. As shown, thetheoretical solar radiation of the SE façade falls within the envelopeof all maximum theoretical values of aggregate curve 192.

FIG. 7C illustrates that if a combi-sensor value from the aggregatecurve 192 is used as input to Module C, all façades have predicted clearsky solar radiation lower than the theoretical values in the aggregatecurve 192. Similarly, if a combi-sensor value from the aggregate curve190 is used as input to Module C, all façades are actually experiencingsolar radiation at or lower than the highest physical sensor value.

Using the illustrated example shown in FIG. 7C, a combi-sensor valuefrom the aggregate curve 190 can be used as input to Module C for the SEfacing facade. The graph shows three regions 195, 196, and 197,generally associated with morning, afternoon, and evening. In themorning region 195, the combi-sensor values from aggregate curve 190 arehigher than the theoretical SE facade value. Since Module C can onlylighten, the higher combi-sensor values do not override the Module A andB tinting decision based on the theoretical radiation of the SE facingfacade. In the afternoon region 196, the combi-sensor values fromaggregate curve 192 are lower than the theoretical SE facade value.Here, Module C would lighten based on the combi-sensor value. In theevening region 197, the combi-sensor values from aggregate curve 190 arehigher than the theoretical SE facade value. Since Module C can onlylighten, the higher combi-sensor value does not override the Module Aand B tinting decision, which would have already maximally cleared thewindow in the early evening.

Method 2—Average Value Method

The second method determines a combi-sensor value at a given time byaveraging the readings taken by all the physical sensors at that time.This second method tends to soften the curve of the combi-sensor valuesand reduce the bounce. In this method, however, the magnitudes of theaverage combi-sensor values may be lower than a single physical sensorreading. Since the combi-sensor value may be much lower, tuning thesecombi-sensor values before inputting them into a control module may bedesired. The difference in magnitude between an average combi-sensorvalue and a single physical sensor reading may be more pronounced as thenumber of physical sensors is increased, in certain circumstances. Thatis, the higher the number of physical sensors, the lower the averagevalue in these cases. Tuning (scaling) to adjust the combi-sensor valuescan be used to get the aggregate values (output) back to realisticlevels. That is, the combi-sensor values may be multiplied by a scalingfactor such as 1.05, 1.1, 1.2, 1.3, 1.4, 1.5, etc. when using theaverage value method.

Method 3—Additive Method

In this third method, the combi-sensor value is determined by summingthe readings at any given time from all the physical sensors. Thismethod results in the highest magnitude combi-sensor value of the threemethods. As with the average method, this third method may requiretuning to return the relative magnitudes back to realistic output e.g.by using a scaling factor. That is, the combi-sensor values may bemultiplied by a scaling factor such as 0.95, 0.9, 0.85, 0.8, 0.75, 0.7,0.65, 0.6, 0.55, 0.50, etc. when using the average value method. In theadditive method, the higher the number of physical sensors, the higherthe aggregate value.

FIG. 8A is a graph including a solar radiation profile 201 (dotted line)based on clear sky predictions of solar radiation on a sunny day on afacade-aligned sensor, according to an embodiment. The graph alsoincludes a curve 202 of simulated solar radiation readings from afaçade-aligned sensor. The graph also includes a curve 203 of returnedtint states (levels) from the logic described in Section X, according toan embodiment.

FIG. 8B is a graph that includes the solar radiation profile 201 (dottedline) of FIG. 8A. The graph also includes an aggregate curve 212 ofcombi-sensor values using the additive method based on clear skypredictions of solar radiation on a sunny day for a combi-sensor systemcomprising three orthogonally-directed physical sensors, according toembodiments. The combi-sensor values are based on summing the readingsat any given time from the three orthogonally-directed physical sensors.The graph also includes a curve 213 of returned tint states from thelogic described in Section X, according to an embodiment.

FIG. 8C is a graph that includes the solar radiation profile 201 (dottedline) of FIG. 8A. The graph also includes an aggregate curve 222 ofcombi-sensor values using the maximum value method based on clear skypredictions of solar radiation on a sunny day for the combi-sensorsystem with three orthogonally-directed physical sensors discussed withrespect to FIG. 8B. The combi-sensor values are based on the maximumreading at any given time from the three orthogonally-directed physicalsensors. The graph also includes a curve 223 of returned tint statesfrom the logic described in Section X, according to an embodiment.

FIG. 8D is a graph that includes the solar radiation profile 201 (dottedline) of FIG. 8A. The graph also includes an aggregate curve 232 ofcombi-sensor values using the average value method based on clear skypredictions of solar radiation on a sunny day for the combi-sensorsystem with three orthogonally-directed physical sensors discussed withrespect to FIG. 8B. The combi-sensor values are based on the averagevalue at any given time of the three orthogonally-directed physicalsensors. The graph also includes a curve 233 of returned tint statesfrom the logic described in Section X, according to an embodiment.

As discussed above, FIGS. 8B-8D include curves of combi-sensor values(readings) based on a combining physical sensor readings from acombi-sensor system with three orthogonally-directed physical sensorstaken on a sunny day, according to an embodiment. The three curves 212,222, and 232 were determined based on the three methods: 1) taking themaximum value of the physical sensor values (Maximum Value Method), 2)averaging the physical sensor values (Average Value Method), and 3)summing the sensor values (Additive Value Method), respectively.

The average value method of determining an aggregate curve has thelowest combi-sensor values of the three methods generally. In themorning, the average value method has combi-sensor values that are lowerthan the values of the theoretical solar radiation profile 201. Inevening, the average value method has combi-sensor values that arehigher than the values of the theoretical solar radiation profile 201.As shown, the additive (summing) method has the highest combi-sensorvalues of the three methods and has higher combi-sensor values than thevalues of the theoretical solar radiation profile 201 throughout day.The maximum value method has combi-sensor values closest to thetheoretical solar radiation profile 201 in the morning and hascombi-sensor values that are higher than the values of the theoreticalsolar radiation profile 201 in the evening.

In some embodiments, certain determinations in the control logic may beadjusted based on the type of combination method used to determine thecombi-sensor value. For example, the threshold value used by Module C inthe logic described in Section X may be adjusted based on the techniqueand method used to determine the combi-sensor value. In this example,the threshold value determines the actual irradiance level outside thatdetermines whether it is a cloudy condition i.e. below this thresholdvalue, it is determined that it is a cloudy day and Module C maydecrease the tint level accordingly overriding Module A/B. In thisexample, the threshold value may be proportionally increased if beingcompared to a combi-sensor value determined with the additive sensormethod or proportionally decreased if being compared to a combi-sensorvalue determined with the average sensor method. Combi-sensor systemscan use one, two or all three of the combination methods to provide acombi-sensor value for a given façade for a given time of day toapproximate as closely as possible the actual irradiance on that façadeand therefore apply tinting algorithms, e.g. Intelligence™ modules,appropriately.

As mentioned above, FIGS. 8A-8D include curves 203, 213, 223, and 233 oftint states returned by the logic described in Section X for anelectrochromic window based on the combi-sensor values of the curves212, 222, and 232 and values in the theoretical solar radiation profile201 respectively. The values in 212, 222, 232, and 202 are based on asunny day. Since in this example, since Module C only lightens(overrides tint commands or does nothing), Module A and B would not beoverridden by Module C in the evening and thus would return a low tintstate based on predicted low irradiance on this facade. Sunny dayperformance of tinting Modules is not compromised by any of the methods,however, the combi-sensor value based on average value is relatively low(as compared to additive) and the threshold value may be proportionallydecreased and the combi-sensor value based on additive value isrelatively high (as compared to average) and the threshold value may beproportionally increased.

FIG. 9 is a graph including theoretical solar radiation readings 240(dotted line) based on clear sky predictions of solar radiation on afacade-aligned sensor. The graph also includes simulated solar radiationreadings 242 on a cloudy day from a facade-aligned sensor. The graphalso includes a curve 244 of returned tint states from the logicdescribed in Section X based on the simulated solar radiation readings242.

FIG. 10A is a graph that includes the solar radiation profile 240(dotted line) of FIG. 9 from a facade-aligned sensor. The graph alsoincludes an aggregate curve 252 of combi-sensor values using the maximumvalue method based on actual solar radiation readings on a cloudy dayfor a combi-sensor system comprising three orthogonally-directedphysical sensors, according to embodiments. The combi-sensor values arebased on the maximum reading at any given time from the threeorthogonally-directed physical sensors. The graph also includes a curve254 of returned tint states from the logic described in Section X,according to an embodiment.

FIG. 10B is a graph that includes the solar radiation profile 240(dotted line) of FIG. 9 on a cloudy day from a facade-aligned sensor.The graph also includes an aggregate curve 262 of combi-sensor valuesusing the additive method based on actual solar radiation readings on acloudy day for a combi-sensor system comprising threeorthogonally-directed physical sensors, according to embodiments. Thecombi-sensor values are based on summing the readings at any given timefrom the three orthogonally-directed physical sensors. The graph alsoincludes a curve 264 of returned tint states from the logic described inSection X, according to an embodiment.

FIG. 10C is a graph that includes the solar radiation profile 240(dotted line) of FIG. 9 on a cloudy day from a facade-aligned sensor.The graph also includes an aggregate curve 272 of combi-sensor valuesusing the additive method based on actual solar radiation readings on acloudy day for a combi-sensor system comprising threeorthogonally-directed physical sensors, according to embodiments. Thecombi-sensor values are based on an average of the readings at any giventime from the three orthogonally-directed physical sensors. The graphalso includes a curve 274 of returned tint states from the logicdescribed in Section X, according to an embodiment.

FIGS. 10A-10C have graphs including the aggregate curves 252, 262, and272 of combi-sensor values determined using simulated readings for acloudy day from three physical sensors of a combi-sensor system,according to an embodiment. The combi-sensor values of the aggregatecurves 252, 262, and 272 were determined based on the three methods: 1)maximum values of three physical sensor values, 2) averaging the sensorvalues, and 3) summing the sensor values, respectively. The aggregatecurves 3520, 3620, and 3720 are based on readings from threeorthogonally-directed physical sensors on a cloudy day. In addition,each graph has a tint state of an electrochromic window that would bereturned by a control system based on the combi-sensor values (bottomgraphs) or the theoretical solar radiation profile (top). When comparingthe methods in this example, the maximum value method retains tailvalues into the afternoon. Using the maximum value method, an EC windowtinting method as described in Section X, would remain tinted longer dueto the higher tail values. Module C performance mirrors sensor whenactive. In the additive sensor method, tinting would be biased to adarker tint state. In the average sensor method, though only 20 minutesdifference from facade-aligned, this method biases to a clearer state.Combi-sensor systems may include operations that select the appropriatecombination of methods to mimic solar exposure at facades having nophysical sensor.

Although combi-sensor systems are not limited to the example of beingused as input to a control system for electrochromic windows, accordingto this example the maximum value method generates combi-sensor valuesthat perform with Module C closest to in-phase façade sensor readingswhen in cloudy conditions. The maximum value method improves sunnycondition performance in this example as well. That is, the maximumvalue method performs better as input to Module C than an out-of phasesensor in sunny conditions. An in-phase sensor refers to a physicalsensor that faces the same direction as the façade orientation. Anout-of-phase sensor refers to a physical sensor that faces a directionthat is not aligned to the direction of the façade. An out-of phasesensor is either trailing (i.e. in a direction with an azimuth angleless than the azimuth angle of the façade orientation) or leading (i.e.in a direction with an azimuth angle more than the azimuth angle of thefaçade orientation). The average value method generates combi-sensorvalues that perform with Module C better than an out-of-phase sensor.The additive method generates combi-sensor values that perform withModule C better than an out-of-phase sensor. All three methods performwith Module C that same as when using readings from an in-phase sensor.

Technique 2

The second technique uses a vector algorithm to interpolate solarradiation readings taken by two or more physical sensors to a virtualfacade-aligned sensor directed at a different azimuth angle. That is,the virtual facade-aligned sensor is typically in a direction that isnot aligned to any of the physical sensors at the structure. In oneembodiment, the combi-sensor value of the virtual facade-aligned sensoris based on two or more of the physical sensors that are closest inazimuthal position to the virtual facade-aligned sensor. In oneembodiment, the combi-sensor value of the virtual facade-aligned sensoris based on all the physical sensors.

FIG. 11 is an example of a solar radiation curve 280 of an interpolatedvirtual facade-aligned sensor as interpolated using a vector algorithmfrom readings of curve 282 taken by a first physical sensor (sensor 1)and readings of curve 284 taken by a second physical sensor (sensor 2)of a combi-sensor system, according to an embodiment. In this example,first physical sensor readings 282 and the second physical sensorreadings 284 are input and used to calculate the solar radiation valueat the virtual facade between the physical sensors. In this case, thevirtual facade-aligned sensor is directed at an azimuth angle betweenthe azimuth angles of the first and second physical sensors (sensor 1and sensor 2). The solar radiation value of the virtual façade-facingsensor at each time can be interpolated from the solar radiation valuesof the first and second physical sensors at the same time. For example,the solar radiation value of the virtual facade-aligned sensor can becalculated as a function of the solar radiation values of the first andsecond physical sensors at the same time. The graph also shows thereadings of the three curves 280, 282, and 284 at 12:40 p.m. Thesemarkers show that by taking the maximum value of the two out of phasesensors readings, the combi-sensor value is covered between the two.

VI. Misaligned Sensor Examples

In some cases, an installed physical sensor may not be properly alignedto its facade or may become misaligned i.e. not facing a normaldirection to the corresponding facade. For example, it may have beimproperly installed, may have become misaligned after installation,etc. In one embodiment, the combi-sensor system may determine the actualorientation of a misaligned physical sensor and adjust its readings foruse at the corresponding facade orientation and/or for use indetermining other combi-sensor values for other facades. To determinethe actual orientation of a misaligned sensor, the combi-sensor systemcould determine the solar radiation profiles (irradiance vs. time) overtwo or more clear sky days for multiple orientations. The solarradiation profiles can be determined from a solar calculator or from anopen-source program such as Radiance. These programs predict clear skyirradiance profiles for many different azimuthal positions. Thecombi-sensor system can compare the solar radiation profiles formultiple orientation s with the sensor output for two or more clear skydays. The combi-sensor system could determine the best matching solarradiation profile to determine the actual orientation to the sensor.Once the actual orientation of the sensor is determined, the readingsfrom this incorrectly oriented sensor can be used to determine acombi-sensor value for a virtual facade-aligned sensor in theorientation of the corresponding facade with the misaligned sensor andfor a virtual sensor in the orientation of other facades not havingphysical sensors.

In one embodiment, a virtual sensor is directed azimuthally with thewall/facade on which the misaligned sensor is mounted. The adjustment isaccomplished by time shifting the misaligned sensor's output tocorrespond with the azimuthal position of the wall/facade. In otherwords, by using the actual position of the sun at a given time, one canapply a time shift factor to the misaligned sensor so that its outputcorresponds with the solar irradiance actually experienced on thefaçade. For example if the sensor is not orthogonal (facing directlyoutward as intended) from a façade, but rather at an angle which wouldallow the sensor to read solar irradiance levels that will beencountered by that façade in 10 minutes. Then a 10 minute time shift isapplied to the sensor's output, for example, the façade's solarirradiance experienced is known 10 minutes prior to the façade actuallybeing exposed to that level of irradiance. So, sensor inputs are read 10minutes prior to the sun actually impinging directly (orthogonally) onthe façade, since the sun is impinging directly on the sensor at thattime.

VII. Combi-Sensor Methods

In general operation, the combi-sensor methods determine a combi-sensorvalue for each facade (or facet thereof) or for a representative facadeof a zone of facades of a building. The combi-sensor value may bedetermined using either Technique 1 (any of the three methods) or byusing Technique 2, as described in detail above. The combi-sensor valuecan be used as input to a one or more building control systems. Forexample, this combi-sensor method can be used to determine acombi-sensor value at each facade having an electrochromic window orother controllable component. The combi-sensor value can then be used bythe control system to adjust the controllable component such as, forexample, transitioning tint state (e.g., increasing tint, clearing,etc.) of an electrochromic window. This is the equivalent to having a“virtual” sensor on facades where no physical sensor is deployed.

In some embodiments, a combi-sensor value may be used as input to ModuleC described in Section X. In the case of a facade having anelectrochromic window, the combi-sensor value can be used as input toModule C to determine whether to decrease tint in the electrochromicwindow based on whether the combi-sensor value is less than a certainvalue such as, for example, the theoretical clear sky irradiance. Insome cases, a combi-sensor value for a representative window of a zoneof electrochromic windows can be used to control the electrochromicwindows in that zone of the building. Although control of electrochromicwindows is described in many examples herein, other building systems maybe controlled using combi-sensor values such as HVAC systems. Forexample, by knowing the solar irradiance on any given façade, the heatload can be managed by increasing or decreasing air conditioning onvarious interior sides of the building.

In embodiments that use Technique 2 to determine the combi-sensor value,the combi-sensor method may determine the two closest physical sensorsto the facade. First, solar radiation readings from three or morephysical sensors in the combi-sensor system are determined for clear skyday(s). In some cases, the physical sensors may take solar radiationreadings for two or more clear sky days to generate “clear sky” solarradiation profiles associated with the directions of the physicalsensors. A solar calculator or from an open-source program such asRadiance may be used to determine expected, theoretical solar radiationprofiles for clear sky days. These programs can generate the theoretical“clear sky” profiles for different azimuthal positions. The actual dailysolar radiation profiles (irradiance vs. time) from readings taken bythe physical sensor(s) over two or more clear sky days can be comparedto the expected theoretical output from the programs. The theoreticalclear sky radiation profile from the program(s) that best agrees withthe actual physical sensor solar radiation profile provides the actualazimuthal position of the physical sensor. The actual azimuthal positionof the physical sensor(s) may be compared with the azimuthal position ofthe facade (e.g., provided in a lookup table) to determine any degree ofmisalignment of the facade with one of the physical sensors. This may berepeated for all the physical sensors in the combi-sensor system. Thiscomparison can be also used to determine which two physical sensors areclosest to the facade and azimuthally contain the facade. The closestphysical sensor to the facade may be determined by comparing the actualazimuthal position of the physical sensors with the azimuthal positionof the facade. The closest physical sensor has the smallest differencein azimuthal position from the facade.

VIII. Virtual Façade-Aligned Sensor Values Used as Input to BuildingControl Systems

As discussed herein, combi-sensor values for facades may be used asinput into building control systems such as thermal/comfort managementsystems. An example of such a building system that controlselectrochromic windows is described in Section X. If used with logicdescribed in Section X, the combi-sensor values may be input into ModuleC for a specific window/zone.

FIGS. 12A-12F illustrate the impacts of different sensor out of phasemisalignments on a building management system for controllingelectrochromic windows as described in Section X, according toembodiments. The impacts on the building management system show theeffects of different degrees of misalignment (either trailing orleading) between a facade and a physical sensor. Misalignments couldcause improper tinting of the window that could be noticeable to theoccupants. In this case, a combi-sensor value determined by Technique 1or Technique 2 may be used to avoid improper tinting.

FIG. 12A shows an example of the impact of out-of-phase sensors whichare trailing the facade, according to embodiments. FIG. 12B shows anexample of the impact of out-of-phase sensors which are leading thefacade, according to embodiments.

FIG. 12A includes a graph with a first solar radiation profile 287 of afacade directed at 180 degrees and a second solar radiation profile 288of readings taken by a physical sensor directed at 170 degrees andtrailing the facade by 10 degrees. FIG. 12A also includes a compassshowing the first azimuth angle 285 of the façade at 180 degrees and thesecond azimuth angle 286 of the physical sensor at 170 degrees. Asdepicted by the clockwise arrow, the physical sensor azimuth angle istrailing the façade so that the sun reaches the physical sensor beforethe façade. Due to this 10 degree misalignment of the physical sensortrailing the façade, the façade is exposed to solar radiation greaterthan the Module C threshold for 50 minutes before the physical sensormeasures radiation greater than the threshold. In the graph shown inFIG. 12A, there is a shaded region 289 from about 1:00 pm to 1:50 pmduring which Module C overrides tint commands (thus clears the windows)for 50 minutes due to misalignment. This is because the sensor readingindicates the solar irradiance is diminished to low levels where ModuleC should override tint values—50 minutes before the solar exposure onthe façade actually diminishes.

FIG. 12B includes a graph with a first solar radiation profile 292 of afacade at 180 degrees and a second solar radiation profile 293 ofreadings taken by a physical sensor directed at 190 degrees and leadingthe facade by 10 degrees. FIG. 12B also includes a compass showing thefirst azimuth angle 290 of the façade at 180 degrees and the secondazimuth angle 291 of the physical sensor at 190 degrees. As depicted bythe clockwise arrow, the physical sensor azimuth angle is leading thefaçade so that the sun reaches the façade before the physical sensor. Inthe graph shown in FIG. 12B, there is a shaded region 294 from about7:50 a.m. to 8:40 a.m. during which Module C overrides for 50 minutesdue to misalignment. In this example, the sensor reads lower solarirradiance levels for 50 minutes after the façade has alreadyexperienced higher solar irradiance levels. Based on these examples, itwas found that that on average during the year if the physical sensor ismisaligned from the facade by 10 degrees, there could be a time ofroughly 50 minutes where the electrochromic window would be erroneouslycleared.

FIGS. 12C-12E each include phase diagrams for illustrating the maximumnumber of minutes Module C can override Module A/B based on the time ofyear, façade azimuth angle, and azimuth angle of the out-of-phasephysical sensor, according to certain embodiments. The circumferentialaxis is in terms of number of degrees that the physical sensor isout-of-phase with the façade orientation. The radial axis is the maximumnumber of minutes Module C would erroneously override Module A/Bincorrectly due to the misalignment of the physical sensor not readingcorrectly the solar irradiation impinging directly on the façade. Thatis, due to its misalignment, would read direct solar exposure during aperiod of time before or after the façade experiences the direct solarexposure. During these time periods, or shifts, Module C woulderroneously override or override incorrectly, due to incorrectphotosensor input as a result of the misalignment. Each phase diagram isfor a specific time of year.

FIG. 12C is a phase diagram for physical sensors leading the facadeduring the winter solstice times, according to embodiments. The phasediagram illustrates the maximum number of minutes Module C canerroneously override Module A/B when using an out of phase physicalsensor that is trailing the façade during the winter solstice. The phasediagram shows a first curve 301 for a physical sensor trailing thefaçade by 40 degrees, a second curve 302 for a physical sensor trailingthe façade by 30 degrees, a third curve 303 for a physical sensortrailing the façade by 20 degrees, and a fourth curve 304 for a physicalsensor trailing the façade by 10 degrees. A line is drawn to show theintersection 305 of the second curve 302 for a physical sensor trailinga façade at 130 degrees by 30 degrees. The phase diagram in FIG. 12Cspecifically illustrates that when a window has an azimuth angle of 130degrees and there is a physical sensor trailing by 30 degrees, thephysical sensor measures readings that are offset in time (time shifted)by 125 minutes. In this case, Module C could erroneously overrideModules A/B during a 125 minute period during the winter solstice if thesensor is misaligned (out of phase) by 30 degrees. Thus the phasediagram may be used in combi-sensor systems to calculate time shiftsnecessary to compensate for out of phase sensors and provide correctsolar irradiation data to, for example, smart window control algorithms.

FIG. 12D is a phase diagram illustrating the yearly maximum impact ofout-of-phase sensors leading the facade, according to embodiments. Thephase diagram shows a first curve 311 for a physical sensor leading thefaçade by 40 degrees, a second curve 312 for a physical sensor leadingthe façade by 30 degrees, a third curve 313 for a physical sensorleading the façade by 20 degrees, and a fourth curve 314 for a physicalsensor leading the façade by 10 degrees. A first line is drawn to showthe intersection 315 of the third curve 313 for a physical sensordirected at 180 degrees leading a façade at 160 degrees by 30 degrees.This illustrates that for a window having an azimuth angle of 160degrees and with a physical sensor leading by 20 degrees, the physicalsensor measures readings that are offset in time (time shifted, andtherefore not reading solar irradiation that is actually hitting thefaçade directly) by about 140 minutes. In this case, Module C coulderroneously override Modules A/B for 140 minutes at some time during theyear if the sensor is misaligned by 20 degrees. A second line is drawnto show the intersection 316 of the fourth curve 314 for a physicalsensor directed at 190 degrees leading a façade at 180 degrees by 10degrees. This illustrates that for a window having an azimuth angle of180 degrees and with a physical sensor leading by 10 degrees, thephysical sensor measures readings that are offset in time (time shifted)by about 50 minutes. In this case, Module C could erroneously overrideModules A/B during this 50 minute window.

FIG. 12E is a phase diagram illustrating the yearly maximum impact of anout of phase sensor trailing the façade, according to an embodiment. Thephase diagram shows a first curve 321 for a physical sensor trailing thefaçade by 40 degrees, a second curve 322 for a physical sensor trailingthe façade by 30 degrees, a third curve 323 for a physical sensortrailing the façade by 20 degrees, and a fourth curve 324 for a physicalsensor trailing the façade by 10 degrees. A first line is drawn to showthe intersection 325 of the second curve 322 for a physical sensordirected at 130 degrees trailing a façade at 160 degrees by 30 degrees.This illustrates that for a window having an azimuth angle of 160degrees and with a physical sensor leading by 30 degrees, the physicalsensor measures readings that are offset in time (time shifted) by about130 minutes. In this case, Module C could erroneously override ModulesA/B during a 130 minute period due to sensor misalignment. A second lineis drawn to show the intersection 326 of the fourth curve 324 for aphysical sensor directed at 190 degrees trailing a façade at 200 degreesby 10 degrees. This illustrates that for a window having an azimuthangle of 200 degrees and with a physical sensor trailing by 10 degrees,the physical sensor measures readings that are offset in time (timeshifted) by about 70 minutes. In this case, Module C could erroneouslyoverride Modules A/B during these 70 minutes.

In certain embodiments, a control method that uses combi-sensor valuesdoes not prematurely override or erroneously override Module A/B on asunny day for any window azimuth angle. A phase diagram of the yearlymaximum impact of using a combi-sensor value based on the maximumapproach method has a single point at the center showing that thecombi-sensor value does not override Module A/B prematurely. In theassociated system, the combi-sensor system has three physical sensorsfacing East, South and West.

FIG. 13A is a graph having theoretical solar radiation profiles fordifferent façade orientations (every 10 degrees) during summer solstice.The graph in FIG. 13A also includes an aggregate curve 330 ofcombi-sensor values for a combi-sensor system during summer solstice,according to an embodiment. FIG. 13B is a graph with the theoreticalsolar radiation profiles for different façade orientations (every 10degrees) during winter solstice. The graph in FIG. 13B also includes anaggregate curve 331 of combi-sensor values for the combi-sensor systemof FIG. 13A during winter solstice, according to an embodiment. In bothFIGS. 13A and 13B, the combi-sensor values were determined using themaximum value method based on the theoretical values. Each of the graphsin FIGS. 13A and 13B include multiple solid lines representingtheoretical physical sensor values at facade orientations spaced 10degrees from each other (0-350). The graph in FIG. 13A also includes anaggregate curve 330 (dashed line) of combi-sensor values which are acombined output of the three physical sensors (East-facing,South-facing, and West-facing) of the combi-sensor system of thisembodiment. The combi-sensor values for the aggregate curve 330 in FIG.13A were determined using the maximum value method. The combi-sensorvalues for the aggregate curve 331 were based on sensor readings from 12sensors separated by 30 degrees from each other.

The aggregate curves (dotted line) cover an envelope under the curves.In FIG. 13A, the theoretical values of all the facades any given azimuthangle fall within the envelope under the aggregate curve.

According to the aggregate curves in FIGS. 13A and 13B, all facades atany given azimuth will be above 100 W/m2 at any given time during theday. The peak value of each of the theoretical solar radiation profilesat each azimuthal value is below the combi-sensor value of the aggregatecurve at nearly all times of the day. All possible facades will fallwithin the combi-sensor aggregate envelope meaning that the combi-sensorwill not falsely send a value to mod C on a sunny day that it wouldinterpret to be a cloudy day due to misalignment.

IX. Ring Sensor Example

In “ring sensor” embodiments, a combi-sensor system generally comprisesa mast and a set of two or more physical sensors (e.g., 12 sensors)mounted to the mast. The physical sensors are facing outward to directthe sensors at distinctly different azimuth angles as discussed insections above. The mast may be installed at/near the structure. Forexample, the mast of the ring sensor may be mounted on the top of abuilding in an unobstructed area. In many cases, the physical sensorsmay be equally-spaced in a ring arrangement (i.e. at the same radiusfrom a central axis of the mast). For example, a ring sensor may becomprised of twelve (12) equally-spaced physical sensors directed atazimuth angles separated by 30 degrees and at/nearly the same radiusfrom the central axis of the mast.

In ring sensor embodiments, the physical sensors may be mounted directlyor indirectly to the mast. In certain aspects, a ring sensor comprises acircular tray mounted to one end of the mast. In these cases, thephysical sensors may be located within this circular tray. A protectivetranslucent casing may be provided over the physical sensors.

FIG. 14A shows a graph having two aggregate curves 352 and 354 ofcombi-sensor values based on readings from a ring sensor comprising fourequally-spaced physical sensors separated by 90 degrees, according to anembodiment. The combi-sensor values in aggregate curves 352 and 354 arebased on the maximum values of the combining readings from the fourequally-spaced physical sensors mounted to the mast of the ring sensorof the embodiment. In the first curve 352, the four equally-spacedphysical sensors are directed in the N, E, S, W directions (maximaloptimal). At the bottom of FIG. 14A, the left compass shows the N, E, S,W directions of the physical sensors. In the second curve 354, the fourequally-spaced physical sensors are directed in NE, SE, SW, NWdirections (minimal optimal). At the bottom of FIG. 14A, the rightcompass shows the NE, SE, SW, NW directions of the physical sensorsafter rotation by 45 degrees. That is, the mast of the ring sensormounted with physical sensors has been rotated by 45 degrees resultingin the combi-sensor values changing from the aggregate curve 352 to theaggregate curve 354. As shown, as the mast of sensors is rotated, themaximum value profile changes. The arrow pointed downward between theaggregate curves 352 and 354 indicates that the combi-sensor valuesdecrease if the mast were to be rotated from N, E, S, and W to NE, SE,SW, and NW directions.

FIGS. 14B-14E are graphs associated with different ring sensorarrangements comprising four (4) physical sensors, eight (8) physicalsensors, twelve (12) physical sensors, and eighteen (18) physicalsensors respectively, according to embodiments. The ring sensorarrangement with 4 sensors has a 90 degrees spacing between adjacentsensors. The ring sensor arrangement with 8 sensors has a 45 degreesspacing between adjacent sensors. The ring sensor arrangement with 12sensors has a 30 degrees spacing between adjacent sensors. The ringsensor arrangement with 18 sensors has a 20 degrees spacing betweenadjacent sensors.

Each of the graphs in FIGS. 14B-14E includes two aggregate curves ofcombi-sensor values determined using the maximum value method by takingthe maximum values of the combined readings from the associatedequally-spaced physical sensors. In each of the graphs in FIGS. 14B-14E,the first curve (360, 370, 380, 390) is associated with theequally-spaced physical sensors in the standard arrangement before beingrotated (maximal optimal). In each of the graphs in FIGS. 14B-14E, thesecond curve (362, 372, 382, 392) is associated with equally-spacedphysical sensors after rotating the mast (minimal optimal) by half thespacing. As shown, the difference between the aggregate curves becomesnegligible for ring sensors having more than 12 sensors with a 30 degreeseparation between the physical sensors.

FIG. 14F is a chart of the maximum difference (delta) between the firstand second aggregate curves from FIGS. 14B-14E for ring sensors havingfour (4), eight (8), twelve (12) and eighteen (18) equally spacedphysical sensors. As shown, the greater the number of physical sensorsin a ring sensor, the lower the maximum difference between all possiblecombi-sensor values in the first and second aggregate curves before andafter rotation of the ring sensor. By comparing the maximum delta fordifferent numbers of physical sensors, increasing the number of physicalsensors beyond twelve (12) yields negligible gains in performance. Basedon this comparison, a ring sensor with twelve (12) or more physicalsensors does not need to be aligned to face particular orientations.That is, any rotation of a ring sensor having more than twelve physicalsensors will have a negligible effect on performance and providedsubstantially the same combi-sensor values.

Ring sensor embodiments may have one or more technical advantages. Forexample, an advantage of a ring sensor embodiment may be ease ofinstallation. If using a ring sensor of more than 12 equally spacedsensors, the sensors do not need to be aligned to certain compassdirections. In addition, the ring sensor may only require a singleinstallation of a pre-constructed arrangement of physical sensors. Thisring sensor embodiment may also avoid certain restrictions placed onsensors installations on the outer facades of the building since thering sensor can be mounted to the top of the building.

X. Building Control Systems

In certain embodiments, a combi-sensor system provides a combi-sensorvalue for a facade of a structure as input to control building systems.For example, combi-sensor values can be used to control thetransitioning to different tint states of one or more electrochromicwindow(s) in a building. Description of control methods fortransitioning to different tint states can be found in PCT/US15/29675,titled “CONTROL METHOD FOR TINTABLE WINDOWS,” and filed on May 7, 2015,and U.S. patent application Ser. No. 13/772,969, titled “CONTROL METHODFOR TINTABLE WINDOWS,” and filed on Feb. 21, 2014, both of which arehereby incorporated by reference in their entirety and for all purposes.An example of a management system for controlling electrochromicwindow(s) and other building systems is described below.

A. Overview of Electrochromic Devices

It should be understood that while disclosed embodiments described belowfocus on electrochromic windows (also referred to as smart windows), theconcepts disclosed herein may apply to other types of tintable windows.For example, a tintable window incorporating a liquid crystal device ora suspended particle device, instead of an electrochromic device couldbe incorporated in any of the disclosed embodiments.

In order to orient the reader to the embodiments of systems, windowcontrollers, and methods disclosed herein, a brief discussion ofelectrochromic devices is provided. This initial discussion ofelectrochromic devices is provided for context only, and thesubsequently described embodiments of systems, window controllers, andmethods are not limited to the specific features and fabricationprocesses of this initial discussion.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

Electrochromic devices having distinct layers can be fabricated as allsolid state devices and/or all inorganic devices. Such devices andmethods of fabricating them are described in more detail in U.S. patentapplication Ser. No. 12/645,111, entitled “Fabrication ofLow-Defectivity Electrochromic Devices,” filed on Dec. 22, 2009, andnaming Mark Kozlowski et al. as inventors, and in U.S. patentapplication Ser. No. 12/645,159, entitled, “Electrochromic Devices,”filed on Dec. 22, 2009 and naming Zhongchun Wang et al. as inventors,both of which are hereby incorporated by reference in their entireties.It should be understood, however, that any one or more of the layers inthe stack may contain some amount of organic material. The same can besaid for liquids that may be present in one or more layers in smallamounts. It should also be understood that solid state material may bedeposited or otherwise formed by processes employing liquid componentssuch as certain processes employing sol-gels or chemical vapordeposition.

Additionally, it should be understood that the reference to a transitionbetween a bleached state and colored state is non-limiting and suggestsonly one example, among many, of an electrochromic transition that maybe implemented. Unless otherwise specified herein (including theforegoing discussion), whenever reference is made to a bleached-coloredtransition, the corresponding device or process encompasses otheroptical state transitions such as non-reflective-reflective,transparent-opaque, etc. Further, the term “bleached” refers to anoptically neutral state, for example, uncolored, transparent, ortranslucent. Still further, unless specified otherwise herein, the“color” of an electrochromic transition is not limited to any particularwavelength or range of wavelengths. As understood by those of skill inthe art, the choice of appropriate electrochromic and counter electrodematerials governs the relevant optical transition.

In embodiments described herein, the electrochromic device reversiblycycles between a bleached state and a colored state. In a similar way,the electrochromic device of embodiments described herein can bereversibly cycled between different tint levels (e.g., bleached state,darkest colored state, and intermediate levels between the bleachedstate and the darkest colored state). In certain aspects, anelectrochromic device may include an electrochromic (EC) electrode layerand a counter electrode (CE) layer separated by an ionically conductive(IC) layer that is highly conductive to ions and highly resistive toelectrons. As conventionally understood, the ionically conductive layertherefore prevents shorting between the electrochromic layer and thecounter electrode layer. The ionically conductive layer allows theelectrochromic and counter electrodes to hold a charge and therebymaintain their bleached or colored states. In electrochromic deviceshaving distinct layers, the components form a stack which includes theion conducting layer sandwiched between the electrochromic electrodelayer and the counter electrode layer. The boundaries between thesethree stack components are defined by abrupt changes in compositionand/or microstructure. Thus, the devices have three distinct layers withtwo abrupt interfaces.

In accordance with certain embodiments, the counter electrode andelectrochromic electrodes are formed immediately adjacent one another,sometimes in direct contact, without separately depositing an ionicallyconducting layer. In some embodiments, electrochromic devices having aninterfacial region rather than a distinct IC layer are employed. Suchdevices, and methods of fabricating them, are described in U.S. Pat. No.8,300,298 and U.S. patent application Ser. No. 12/772,075 filed on Apr.30, 2010, and U.S. patent application Ser. Nos. 12/814,277 and12/814,279, filed on Jun. 11, 2010—each of the three patent applicationsand patent is entitled “Electrochromic Devices,” each names ZhongchunWang et al. as inventors, and each is incorporated by reference hereinin its entirety.

B. Window Controllers

A window controller is used to control the tint level of theelectrochromic device of an electrochromic window. In some embodiments,the window controller is able to transition the electrochromic windowbetween two tint states (levels), a bleached state and a colored state.In other embodiments, the controller can additionally transition theelectrochromic window (e.g., having a single electrochromic device) tointermediate tint levels. In some disclosed embodiments, the windowcontroller is able to transition the electrochromic window to four ormore tint levels. Certain electrochromic windows allow intermediate tintlevels by using two (or more) electrochromic lites in a single IGU,where each lite is a two-state lite.

In some embodiments, an electrochromic window can include anelectrochromic device on one lite of an IGU and another electrochromicdevice on the other lite of the IGU. If the window controller is able totransition each electrochromic device between two states, a bleachedstate and a colored state, the electrochromic window is able to attainfour different states (tint levels), a colored state with bothelectrochromic devices being colored, a first intermediate state withone electrochromic device being colored, a second intermediate statewith the other electrochromic device being colored, and a bleached statewith both electrochromic devices being bleached. Embodiments ofmulti-pane electrochromic windows are further described in U.S. Pat. No.8,270,059, naming Robin Friedman et al. as inventors, titled “MULTI-PANEELECTROCHROMIC WINDOWS,” which is hereby incorporated by reference inits entirety.

In some embodiments, the window controller is able to transition anelectrochromic window having an electrochromic device capable oftransitioning between two or more tint levels. For example, a windowcontroller may be able to transition the electrochromic window to ableached state, one or more intermediate levels, and a colored state. Insome other embodiments, the window controller is able to transition anelectrochromic window incorporating an electrochromic device between anynumber of tint levels between the bleached state and the colored state.Embodiments of methods and controllers for transitioning anelectrochromic window to an intermediate tint level or levels arefurther described in U.S. Pat. No. 8,254,013, naming Disha Mehtani etal. as inventors, titled “CONTROLLING TRANSITIONS IN OPTICALLYSWITCHABLE DEVICES,” which is hereby incorporated by reference in itsentirety.

In some embodiments, a window controller can power one or moreelectrochromic devices in an electrochromic window. Typically, thisfunction of the window controller is augmented with one or more otherfunctions described in more detail below. Window controllers describedherein are not limited to those that have the function of powering anelectrochromic device to which it is associated for the purposes ofcontrol. That is, the power source for the electrochromic window may beseparate from the window controller, where the controller has its ownpower source and directs application of power from the window powersource to the window. However, it is convenient to include a powersource with the window controller and to configure the controller topower the window directly, because it obviates the need for separatewiring for powering the electrochromic window.

Further, the window controllers described in this section are describedas standalone controllers which may be configured to control thefunctions of a single window or a plurality of electrochromic windows,without integration of the window controller into a building controlnetwork or a building management system (BMS). Window controllers,however, may be integrated into a building control network or a BMS, asdescribed further in the Building Management System section of thisdisclosure.

FIG. 15 depicts a block diagram of some components of a windowcontroller 450 and other components of a window controller system ofdisclosed embodiments. FIG. 15 is a simplified block diagram of a windowcontroller, and more detail regarding window controllers can be found inU.S. patent application Ser. Nos. 13/449,248 and 13/449,251, both namingStephen Brown as inventor, both titled “CONTROLLER FOROPTICALLY-SWITCHABLE WINDOWS,” and both filed on Apr. 17, 2012, and inU.S. patent Ser. No. 13/449,235, titled “CONTROLLING TRANSITIONS INOPTICALLY SWITCHABLE DEVICES,” naming Stephen Brown et al. as inventorsand filed on Apr. 17, 2012, all of which are hereby incorporated byreference in their entireties.

In FIG. 15, the illustrated components of the window controller 450include a window controller 450 having a microprocessor 455 or otherprocessor, a power width modulator (PWM) 460, a signal conditioningmodule 465, and a computer readable medium (e.g., memory) having aconfiguration file 475. Window controller 450 is in electroniccommunication with one or more electrochromic devices 400 in anelectrochromic window through network 480 (wired or wireless) to sendinstructions to the one or more electrochromic devices 400. In someembodiments, the window controller 450 may be a local window controllerin communication through a network (wired or wireless) to a masterwindow controller.

In disclosed embodiments, a building may have at least one room havingan electrochromic window between the exterior and interior of abuilding. One or more sensors may be located to the exterior of thebuilding and/or inside the room. In embodiments, the output from the oneor more sensors may be input to the signal conditioning module 465 ofthe window controller 450. In some cases, the output from the one ormore sensors may be input to a BMS, as described further in the BuildingManagement Systems section. Although the sensors of depicted embodimentsare shown as located on the outside vertical wall of the building, thisis for the sake of simplicity, and the sensors may be in otherlocations, such as inside the room or on other surfaces to the exterior,as well. In some cases, two or more sensors may be used to measure thesame input, which can provide redundancy in case one sensor fails or hasan otherwise erroneous reading.

FIG. 16A depicts a schematic diagram of a room 500 having anelectrochromic window 505 with at least one electrochromic device. Theelectrochromic window 505 is located between the exterior and theinterior of a building, which includes the room 500. The room 500 alsoincludes a window controller 450 connected to and configured to controlthe tint level of the electrochromic window 505. An exterior sensor 510is located on a vertical surface in the exterior of the building. Inother embodiments, an interior sensor may also be used to measure theambient light in room 500. In yet other embodiments, an occupant sensormay also be used to determine when an occupant is in the room 500.

Exterior sensor 510 is a device, such as a photosensor, that is able todetect radiant light incident upon the device flowing from a lightsource such as the sun or from light reflected to the sensor from asurface, particles in the atmosphere, clouds, etc. The exterior sensor510 may generate a signal in the form of electrical current that resultsfrom the photoelectric effect and the signal may be a function of thelight incident on the sensor 510. In some cases, the device may detectradiant light in terms of irradiance in units of watts/m² or othersimilar units. In other cases, the device may detect light in thevisible range of wavelengths in units of foot candles or similar units.In many cases, there is a linear relationship between these values ofirradiance and visible light.

Irradiance values from sunlight can be predicted based on the time ofday and time of year as the angle at which sunlight strikes the earthchanges. Exterior sensor 510 can detect radiant light in real-time,which accounts for reflected and obstructed light due to buildings,changes in weather (e.g., clouds), etc. For example, on cloudy days,sunlight would be blocked by the clouds and the radiant light detectedby an exterior sensor 510 would be lower than on cloudless days.

In some embodiments, there may be one or more exterior sensors 510associated with a single electrochromic window 505. Output from the oneor more exterior sensors 510 could be compared to one another todetermine, for example, if one of exterior sensors 510 is shaded by anobject, such as by a bird that landed on exterior sensor 510. In somecases, it may be desirable to use relatively few sensors in a buildingbecause some sensors can be unreliable and/or expensive. In certainimplementations, a single sensor or a few sensors may be employed todetermine the current level of radiant light from the sun impinging onthe building or perhaps one side of the building. A cloud may pass infront of the sun or a construction vehicle may park in front of thesetting sun. These will result in deviations from the amount of radiantlight from the sun calculated to normally impinge on the building.

Exterior sensor 510 may be a type of photosensor. For example, exteriorsensor 510 may be a charge coupled device (CCD), photodiode,photoresistor, or photovoltaic cell. One of ordinary skill in the artwould appreciate that future developments in photosensor and othersensor technology would also work, as they measure light intensity andprovide an electrical output representative of the light level.

In some embodiments, output from exterior sensor 510 may be input to thesignal conditioning module 465. The input may be in the form of avoltage signal to signal conditioning module 465. Signal conditioningmodule 465 passes an output signal to the window controller 450. Windowcontroller 450 determines a tint level of the electrochromic window 505,based on various information from the configuration file 475, outputfrom the signal conditioning module 465, override values. Windowcontroller 450 and then instructs the PWM 460, to apply a voltage and/orcurrent to electrochromic window 505 to transition to the desired tintlevel.

In disclosed embodiments, window controller 450 can instruct the PWM460, to apply a voltage and/or current to electrochromic window 505 totransition it to any one of four or more different tint levels. Indisclosed embodiments, electrochromic window 505 can be transitioned toat least eight different tint levels described as: 0 (lightest), 5, 10,15, 20, 25, 30, and 35 (darkest). The tint levels may linearlycorrespond to visual transmittance values and solar gain heatcoefficient (SGHC) values of light transmitted through theelectrochromic window 505. For example, using the above eight tintlevels, the lightest tint level of 0 may correspond to an SGHC value of0.80, the tint level of 5 may correspond to an SGHC value of 0.70, thetint level of 10 may correspond to an SGHC value of 0.60, the tint levelof 15 may correspond to an SGHC value of 0.50, the tint level of 20 maycorrespond to an SGHC value of 0.40, the tint level of 25 may correspondto an SGHC value of 0.30, the tint level of 30 may correspond to an SGHCvalue of 0.20, and the tint level of 35 (darkest) may correspond to anSGHC value of 0.10.

Window controller 450 or a master controller in communication with thewindow controller 450 may employ any one or more predictive controllogic components to determine a desired tint level based on signals fromthe exterior sensor 510 and/or other input. The window controller 450can instruct the PWM 460 to apply a voltage and/or current toelectrochromic window 505 to transition it to the desired tint level.

C. An Example of Predictive Control Logic

In disclosed embodiments, predictive control logic is used to implementmethods of determining and controlling a desired tint level for theelectrochromic window 505 or other tintable window that accounts foroccupant comfort and/or energy conservation considerations. Thispredictive control logic may employ one or more logic modules. FIGS.16A-16C include diagrams depicting some information collected by each ofthree logic modules A, B, and C of an exemplary control logic ofdisclosed embodiments.

FIG. 16A shows the penetration depth of direct sunlight into a room 500through an electrochromic window 505 between the exterior and theinterior of a building, which includes the room 500. Penetration depthis a measure of how far direct sunlight will penetrate into the room500. As shown, penetration depth is measured in a horizontal directionaway from the sill (bottom) of window. Generally, the window defines anaperture that provides an acceptance angle for direct sunlight. Thepenetration depth is calculated based upon the geometry of the window(e.g., window dimensions), its position and orientation in the room, anyfins or other exterior shading outside of the window, and the positionof the sun (e.g. angle of direct sunlight for a particular time of dayand date). Exterior shading to an electrochromic window 505 may be dueto any type of structure that can shade the window such as an overhang,a fin, etc. In FIG. 16A, there is an overhang 520 above theelectrochromic window 505 that blocks a portion of the direct sunlightentering the room 500 thus shortening the penetration depth. The room500 also includes a local window controller 450 connected to andconfigured to control the tint level of the electrochromic window 505.An exterior sensor 510 is located on a vertical surface in the exteriorof the building.

Module A can be used to determine a tint level that considers occupantcomfort from direct sunlight through the electrochromic window 505 ontoan occupant or their activity area. The tint level is determined basedon a calculated penetration depth of direct sunlight into the room andthe space type (e.g., desk near window, lobby, etc.) in the room at aparticular instant in time. In some cases, the tint level may also bebased on providing sufficient natural lighting into the room. In manycases, the penetration depth is the value calculated at a time in thefuture to account for glass transition time. The concern addressed inModule A is that direct sunlight may penetrate so deep into the room 500as to show directly on an occupant working at a desk or other worksurface in a room. Publicly available programs can provide calculationof the sun's position and allow for easy calculation of penetrationdepth.

FIG. 16A also shows a desk in the room 500 as an example of a space typeassociated with an activity area (i.e. desk) and location of theactivity area (i.e. location of desk). Each space type is associatedwith different tint levels for occupant comfort. For example, if theactivity is a critical activity such as work in an office being done ata desk or computer, and the desk is located near the window, the desiredtint level may be higher than if the desk were further away from thewindow. As another example, if the activity is non-critical, such as theactivity in a lobby, the desired tint level may be lower than for thesame space having a desk.

FIG. 16B shows direct sunlight and radiation under clear sky conditionsentering the room 500 through the electrochromic window 505. Theradiation may be from sunlight scattered by molecules and particles inthe atmosphere. Module B determines a tint level based on predictedvalues of irradiance under clear sky conditions flowing through theelectrochromic window 505 under consideration. Various software, such asopen source RADIANCE program, can be used to predict clear skyirradiance at a certain latitude, longitude, time of year, and time ofday, and for a given window orientation.

FIG. 16C shows radiant light from the sky that is measured in real-timeby an exterior sensor 510 to account for light that may be obstructed byor reflected from objects such as buildings or weather conditions (e.g.,clouds) that are not accounted for in the clear sky predictions. Thetint level determined by Module C is based on the real-time irradiancebased on measurements taken by the exterior sensor 510.

The predictive control logic may implement one or more of the logicModules A, B and C separately for each electrochromic window 505 in thebuilding. Each electrochromic window 505 can have a unique set ofdimensions, orientation (e.g., vertical, horizontal, tilted at anangle), position, associated space type, etc. A configuration file withthis information and other information can be maintained for eachelectrochromic window 505. The configuration file 475 may be stored inthe computer readable medium 470 of the local window controller 450 ofthe electrochromic window 505 or in the BMS described later in thisdisclosure. The configuration file 475 can include information such as awindow configuration, an occupancy lookup table, information about anassociated datum glass, and/or other data used by the predictive controllogic. The window configuration may include information such as thedimensions of the electrochromic window 505, the orientation of theelectrochromic window 505, the position of the electrochromic window505, etc.

A lookup table describes tint levels that provide occupant comfort forcertain space types and penetration depths. That is, the tint levels inthe occupancy lookup table are designed to provide comfort tooccupant(s) that may be in the room 500 from direct sunlight on theoccupant(s) or their workspace. An example of an occupancy lookup tableis shown in FIG. 20.

The space type is a measure to determine how much tinting will berequired to address occupant comfort concerns for a given penetrationdepth and/or provide comfortable natural lighting in the room. The spacetype parameter may take into consideration many factors. Among thesefactors is the type of work or other activity being conducted in aparticular room and the location of the activity. Close work associatedwith detailed study requiring great attention might be at one spacetype, while a lounge or a conference room might have a different spacetype. Additionally, the position of the desk or other work surface inthe room with respect to the window is a consideration in defining thespace type. For example, the space type may be associated with an officeof a single occupant having a desk or other workspace located near theelectrochromic window 505. As another example, the space type may be alobby.

In certain embodiments, one or more modules of the predictive controllogic can determine desired tint levels while accounting for energyconservation in addition to occupant comfort. These modules maydetermine energy savings associated with a particular tint level bycomparing the performance of the electrochromic window 505 at that tintlevel to a datum glass or other standard reference window. The purposeof using this reference window can be to ensure that the predictivecontrol logic conforms to requirements of the municipal building code orother requirements for reference windows used in the locale of thebuilding. Often municipalities define reference windows usingconventional low emissivity glass to control the amount of airconditioning load in the building. As an example of how the referencewindow 505 fits into the predictive control logic, the logic may bedesigned so that the irradiance coming through a given electrochromicwindow 505 is never greater than the maximum irradiance coming through areference window as specified by the respective municipality. Indisclosed embodiments, predictive control logic may use the solar heatgain coefficient (SHGC) value of the electrochromic window 505 at aparticular tint level and the SHGC of the reference window to determinethe energy savings of using the tint level. Generally, the value of theSHGC is the fraction of incident light of all wavelengths transmittedthrough the window. Although a datum glass is described in manyembodiments, other standard reference windows can be used. Generally theSHGC of the reference window (e.g., datum glass) is a variable that canbe different for different geographical locations and windoworientations, and is based on code requirements specified by therespective municipality.

Generally, buildings are designed to have an HVAC with the capacity tofulfill the maximum expected heating and/or air-conditioning loadsrequired at any given instance. The calculation of required capacity maytake into consideration the datum glass or reference window required ina building at the particular location where the building is beingconstructed. Therefore, it is important that the predictive controllogic meet or exceed the functional requirements of the datum glass inorder to allow building designers to confidently determine how much HVACcapacity to put into a particular building. Since the predictive controllogic can be used to tint the window to provide additional energysavings over the datum glass, the predictive control logic could beuseful in allowing building designers to have a lower HVAC capacity thanwould have been required using the datum glass specified by the codesand standards.

Particular embodiments described herein assume that energy conservationis achieved by reducing air conditioning load in a building. Therefore,many of the implementations attempt to achieve the maximum tintingpossible, while accounting for occupant comfort level and perhapslighting load in a room having with the window under consideration.However, in some climates, such as those at far northern and forsouthern latitudes, heating may be more of a concern than airconditioning. Therefore, the predictive control logic can be modified,specifically, road reversed in some matters, so that less tinting occursin order to ensure that the heating load of the building is reduced.

In certain implementations, the predictive control logic has only twoindependent variables that can be controlled by an occupant (end user),building designer, or building operator. These are the space types for agiven window and the datum glass associated with the given window. Oftenthe datum glass is specified when the predictive control logic isimplemented for a given building. The space type can vary, but istypically static. In certain implementations, the space type may be partof the configuration file maintained by the building or stored in thelocal window controller 450. In some cases, the configuration file maybe updated to account for various changes in the building. For example,if there is a change in the space type (e.g., desk moved in an office,addition of desk, lobby changed into office area, wall moved, etc.) inthe building, an updated configuration file with a modified occupancylookup table may be stored in the computer readable medium 470. Asanother example, if an occupant is hitting manual override repeatedly,then the configuration file may be updated to reflect the manualoverride.

FIG. 17 is a flowchart showing predictive control logic for a method ofcontrolling one or more electrochromic windows 505 in a building,according to embodiments. The predictive control logic uses one or moreof the Modules A, B, and C to calculate tint levels for the window(s)and sends instructions to transition the window(s). The calculations inthe control logic are run 1 to n times at intervals timed by the timerat step 610. For example, the tint level can be recalculated 1 to ntimes by one or more of the Modules A, B, and C and calculated forinstances in time t_(i)=t₁, t₂ . . . t_(n). n is the number ofrecalculations performed and n can be at least 1. The logic calculationscan be done at constant time intervals in some cases. In one cases, thelogic calculations may be done every 2 to 5 minutes. However, tinttransition for large pieces of electrochromic glass can take up to 30minutes or more. For these large windows, calculations may be done on aless frequent basis such as every 30 minutes.

At step 620, logic Modules A, B, and C perform calculations to determinea tint level for each electrochromic window 505 at a single instant intime t_(i). These calculations can be performed by the window controller450. In certain embodiments, the predictive control logic predictivelycalculates how the window should transition in advance of the actualtransition. In these cases, the calculations in Modules A, B, and C canbe based on a future time around or after transition is complete. Inthese cases, the future time used in the calculations may be a time inthe future that is sufficient to allow the transition to be completedafter receiving the tint instructions. In these cases, the controllercan send tint instructions in the present time in advance of the actualtransition. By the completion of the transition, the window will havetransitioned to a tint level that is desired for that time.

At step 630, the predictive control logic allows for certain types ofoverrides that disengage the algorithm at Modules A, B, and C and defineoverride tint levels at step 640 based on some other consideration. Onetype of override is a manual override. This is an override implementedby an end user who is occupying a room and determines that a particulartint level (override value) is desirable. There may be situations wherethe user's manual override is itself overridden. An example of anoverride is a high demand (or peak load) override, which is associatedwith a requirement of a utility that energy consumption in the buildingbe reduced. For example, on particularly hot days in large metropolitanareas, it may be necessary to reduce energy consumption throughout themunicipality in order to not overly tax the municipality's energygeneration and delivery systems. In such cases, the building mayoverride the tint level from the predictive control logic describedherein to ensure that all windows have a particularly high level oftinting. Another example of an override may be if there is no occupantin the room, for example during a weekend in a commercial officebuilding. In these cases, the building may disengage one or more Modulesthat relate to occupant comfort and all the windows may have a highlevel of tinting in cold weather and low level of tinting in warmweather.

At step 650, the tint levels are transmitted over a network toelectrochromic device(s) in one or more electrochromic windows 505 inthe building. In certain embodiments, the transmission of tint levels toall windows of a building may be implemented with efficiency in mind.For example, if the recalculation of tint level suggests that no changein tint from the current tint level is required, then there is notransmission of instructions with an updated tint level. As anotherexample, the building may be divided into zones based on window size.The predictive control logic may recalculate tint levels for zones withsmaller windows more frequently than for zones with larger windows.

In some embodiments, the logic in FIG. 17 for implementing the controlmethods for multiple electrochromic windows 505 in an entire buildingcan be on a single device, for example, a single master windowcontroller. This device can perform the calculations for each and everywindow in the building and also provide an interface for transmittingtint levels to one or more electrochromic devices in individualelectrochromic windows 505.

Also, there may be certain adaptive components of the predictive controllogic of embodiments. For example, the predictive control logic maydetermine how an end user (e.g. occupant) tries to override thealgorithm at particular times of day and makes use of this informationin a more predictive manner to determine desired tint levels. In onecase, the end user may be using a wall switch to override the tint levelprovided by the predictive logic at a certain time each day to anoverride value. The predictive control logic may receive informationabout these instances and change the predictive control logic to changethe tint level to the override value at that time of day.

FIG. 18 is a diagram showing a particular implementation of block 620from FIG. 17. This diagram shows a method of performing all threeModules A, B, and C in sequence to calculate a final tint level of aparticular electrochromic window 505 for a single instant in time t_(i).The final tint level may be the maximum permissible transmissivity ofthe window under consideration. FIG. 18 also includes some exemplaryinputs and outputs of Modules A, B, and C. The calculations in ModulesA, B, and C are performed by window controller 450 in local windowcontroller 450 in embodiments. In other embodiments, one or more of themodules can be performed by another processor. Although illustratedembodiments show all three Modules A, B, and C being used, otherembodiments may use one or more of the Modules A, B, and C or may useadditional modules.

At step 700, window controller 450 uses Module A to determine a tintlevel for occupant comfort to prevent direct glare from sunlightpenetrating the room 500. Window controller 450 uses Module A tocalculate the penetration depth of direct sunlight into the room 500based on the sun's position in the sky and the window configuration fromthe configuration file. The position of the sun is calculated based onthe latitude and longitude of the building and the time of day and date.The occupancy lookup table and space type are input from a configurationfile for the particular window. Module A outputs the Tint level from Ato Module B.

The goal of Module A is to ensure that direct sunlight or glare does notstrike the occupant or his or her workspace. The tint level from ModuleA is determined to accomplish this purpose. Subsequent calculations oftint level in Modules B and C can reduce energy consumption and mayrequire even greater tint. However, if subsequent calculations of tintlevel based on energy consumption suggest less tinting than required toavoid interfering with the occupant, the predictive logic prevents thecalculated greater level of transmissivity from being executed to assureoccupant comfort.

At step 800, the tint level calculated in Module A is input into ModuleB. A tint level is calculated based on predictions of irradiance underclear sky conditions (clear sky irradiance). Window controller 450 usesModule B to predict clear sky irradiance for the electrochromic window505 based on window orientation from the configuration file and based onlatitude and longitude of the building. These predictions are also basedon a time of day and date. Publicly available software such as theRADIANCE program, which is an open-source program, can provide thecalculations for predicting clear sky irradiance. The SHGC of the datumglass is also input into Module B from the configuration file. Windowcontroller 450 uses Module B to determine a tint level that is darkerthan the tint level in A and transmits less heat than the datum glass ispredicted to transmit under maximum clear sky irradiance. Maximum clearsky irradiance is the highest level of irradiance for all timespredicted for clear sky conditions.

At step 900, a tint level from B and predicted clear sky irradiance areinput to Module C. Real-time irradiance values are input to Module Cbased on measurements from an exterior sensor 510. Window controller 450uses Module C to calculate irradiance transmitted into the room if thewindow were tinted to the Tint level from Module B under clear skyconditions. Window controller 450 uses Module C to find the appropriatetint level where the actual irradiance through the window with this tintlevel is less than or equal to the irradiance through the window withthe Tint level from Module B. The tint level determined in Module C isthe final tint level.

Much of the information input to the predictive control logic isdetermined from fixed information about the latitude and longitude, timeand date. This information describes where the sun is with respect tothe building, and more particularly with respect to the window for whichthe predictive control logic is being implemented. The position of thesun with respect to the window provides information such as thepenetration depth of direct sunlight into the room assisted with thewindow. It also provides an indication of the maximum irradiance orsolar radiant energy flux coming through the window. This calculatedlevel of irradiance can be modified by sensor input which might indicatethat there is a reduction from the maximum amount of irradiance. Again,such reduction might be caused by a cloud or other obstruction betweenthe window and the sun.

FIG. 19 is a flowchart showing details of step 700 of FIG. 18. At step705, Module A begins. At step 710, the window controller 450 uses ModuleA to calculate the position of the sun for the latitude and longitudecoordinates of the building and the date and time of day of a particularinstant in time, t_(i). The latitude and longitude coordinates may beinput from the configuration file. The date and time of day may be basedon the current time provided by the timer. The sun position iscalculated at the particular instant in time, t_(i), which may be in thefuture in some cases. In other embodiments, the position of the sun iscalculated in another component (e.g., module) of the predictive controllogic.

At step 720, window controller 450 uses Module A to calculate thepenetration depth of direct sunlight into the room 500 at the particularinstant in time used in step 710. Module A calculates the penetrationdepth based on the calculated position of the sun and windowconfiguration information including the position of the window,dimensions of the window, orientation of the window (i.e. directionfacing), and the details of any exterior shading. The windowconfiguration information is input from the configuration fileassociated with the electrochromic window 505. For example, Module A canbe used to calculate the penetration depth of the vertical window shownin FIG. 16A by first calculating the angle θ of the direct sunlightbased on the position of the sun calculated at the particular instant intime. The penetration depth can be determined based on calculated angleθ and the location of the lintel (top of the window).

At step 730, a tint level is determined that will provide occupantcomfort for the penetration depth calculated in step 720. The occupancylookup table is used to find a desired tint level for the space typeassociated with the window, for the calculated penetration depth, andfor the acceptance angle of the window. The space type and occupancylookup table are provided as input from the configuration file for theparticular window.

An example of an occupancy lookup table is provided in FIG. 20. Thevalues in the table are in terms of a Tint level and associated SGHCvalues in parenthesis. FIG. 20 shows the different tint levels (SGHCvalues) for different combinations of calculated penetration values andspace types. The table is based on eight tint levels including 0(lightest), 5, 10, 15, 20, 25, 30, and 35 (lightest). The lightest tintlevel of 0 corresponds to an SGHC value of 0.80, the tint level of 5corresponds to an SGHC value of 0.70, the tint level of 10 correspondsto an SGHC value of 0.60, the tint level of 15 corresponds to an SGHCvalue of 0.50, the tint level of 20 corresponds to an SGHC value of0.40, the tint level of 25 corresponds to an SGHC value of 0.30, thetint level of 30 corresponds to an SGHC value of 0.20, and the tintlevel of 35 (darkest) corresponds to an SGHC value of 0.10. Theillustrated example includes three space types: Desk 1, Desk 2, andLobby and six penetration depths. FIG. 21A shows the location of Desk 1in the room 500. FIG. 21B shows the location of Desk 2 in the room 500.As shown in the occupancy lookup table of FIG. 20, the tint levels forDesk 1 close to the window are higher than the tint levels for Desk 2far from window to prevent glare when the desk is closer to the window.Occupancy lookup tables with other values may be used in otherembodiments. For example, one other occupancy lookup table may includeonly four tint levels associated with the penetration values.

FIG. 22 is a diagram showing further detail of step 800 of FIG. 18. Atstep 805, Module B begins. At step 810, Module B can be used to predictthe irradiance at the window under clear sky conditions at t_(i). Thisclear sky irradiance at t_(i) is predicted based on the latitude andlongitude coordinates of the building and the window orientation (i.e.direction the window is facing). At step 820, the Maximum Clear SkyIrradiance incident the window at all times is predicted. Thesepredicted values of clear sky irradiance can be calculated using opensource software, such as Radiance.

At step 830, the window controller 450 uses Module B to determine themaximum amount of irradiance that would be transmitted through a datumglass into the room 500 at that time (i.e. determines Maximum DatumInside Irradiance). The calculated Maximum Clear Sky Irradiance fromstep 820 and the datum glass SHGC value from the configuration file canbe used to calculate the Maximum Irradiance inside the space using theequation: Maximum Datum Inside Irradiance=Datum Glass SHGC×Maximum ClearSky Irradiance.

At step 840, window controller 450 uses Module B to determine insideirradiance into the room 500 having a window with the current tint levelbased on the equation. The calculated Clear Sky Irradiance from step 810and the SHGC value associated with the current tint level can be used tocalculate the value of the inside irradiance using the equation: Tintlevel Irradiance=Tint level SHGC×Clear Sky Irradiance.

In one embodiment, one or more the steps 705, 810 and 820 may beperformed by a solar position calculator separate from Modules A and B.A solar position calculator refers to logic that determines the positionof the sun at a particular future time and makes predictivedeterminations (e.g., predicts clear sky irradiance) based on the sun'sposition at that future time. The solar position calculator may performone or more steps of the methods disclosed herein. The solar positioncalculator may be a portion of the predictive control logic performed byone or more of the components of the master window controller. Forexample, the solar position calculator may be part of the predictivecontrol logic shown in FIG. 25 implemented by the window controller1410.

At step 850, window controller 450 uses Module B to determine whetherthe inside irradiance based on the current tint level is less than orequal to the maximum datum inside irradiance and the tint level isdarker than the tint level from A. If the determination is NO, thecurrent tint level is incrementally increased (darkened) at step 860 andthe inside irradiance is recalculated at step 840. If the determinationis YES at step 850, Module B ends.

FIG. 23 is a diagram showing further detail of step 900 of FIG. 18. Atstep 905, Module C begins. A tint level from B and predicted clear skyirradiance at the instant in time t_(i) is input from Module B.Real-time irradiance values are input to Module C based on measurementsfrom an exterior sensor 510.

At step 910, window controller 450 uses Module C to calculate irradiancetransmitted into the room through an electrochromic window 505 tinted tothe Tint level from B under clear sky conditions. This Calculated InsideIrradiance can be determined using the equation: Calculated InsideIrradiance=SHGC of Tint Level from B×Predicted Clear Sky Irradiance fromB.

At step 920, window controller 450 uses Module C to find the appropriatetint level where the actual irradiance (=SR×Tint level SHGC) through thewindow with this tint level is less than or equal to the irradiancethrough the window with the Tint level from B (i.e. Actual InsideIrradiance≦Calculated Inside Irradiance). In some cases, the modulelogic starts with the tint level from B and incrementally increases thetint level until the Actual Inside Irradiance≦Calculated InsideIrradiance. The tint level determined in Module C is the final tintlevel. This final tint level may be transmitted in tint instructionsover the network to the electrochromic device(s) in the electrochromicwindow 505.

FIG. 24 is a diagram includes another implementation of block 620 fromFIG. 17. This diagram shows a method of performing Modules A, B, and Cof embodiments. In this method, the position of the sun is calculatedbased on the latitude and longitude coordinates of the building for asingle instant in time t_(i). The penetration depth is calculated inModule A based on the window configuration including a position of thewindow, dimensions of the window, orientation of the window, andinformation about any external shading. Module A uses a lookup table todetermine the tint level from A based on the calculated penetration andthe space type. The tint level from A is then input into Module B.

A program such as the open source program Radiance, is used to determineclear sky irradiance based on window orientation and latitude andlongitude coordinates of the building for both a single instant in timet_(i) and a maximum value for all times. The datum glass SHGC andcalculated maximum clear sky irradiance are input into Module B. ModuleB increases the tint level calculated in Module A in steps and picks atint level where the Inside radiation is less than or equal to the DatumInside Irradiance where: Inside Irradiance=Tint level SHGC×Clear SkyIrradiance and Datum Inside Irradiance=Datum SHGC×Maximum Clear SkyIrradiance. However, when Module A calculates the maximum tint of theglass, module B doesn't change the tint to make it lighter. The tintlevel calculated in B is then input into Module C. The predicted clearsky irradiance is also input into Module C.

Module C calculates the inside irradiance in the room with anelectrochromic window 505 having the tint level from B using theequation: Calculated Inside Irradiance=SHGC of Tint Level fromB×Predicted Clear Sky Irradiance from B. Module C then finds theappropriate tint level that meets the condition where actual insideirradiance is less than or equal to the Calculated Inside Irradiance.The actual inside irradiance is determined using the equation: ActualInside Irradiance=SR×Tint level SHGC. The tint level determined byModule C is the final tint level in tint instructions sent to theelectrochromic window 505.

In some embodiments, tintable windows for the exterior windows of thebuilding (i.e., windows separating the interior of the building from theexterior of the building), may be grouped into zones, with tintablewindows in a zone being instructed in a similar manner. For example,groups of electrochromic windows on different floors of the building ordifferent sides of the building may be in different zones. For example,on the first floor of the building, all of the east facingelectrochromic windows may be in zone 1, all of the south facingelectrochromic windows may be in zone 2, all of the west facingelectrochromic windows may be in zone 3, and all of the north facingelectrochromic windows may be in zone 4. As another example, all of theelectrochromic windows on the first floor of the building may be in zone1, all of the electrochromic windows on the second floor may be in zone2, and all of the electrochromic windows on the third floor may be inzone 3. As yet another example, all of the east facing electrochromicwindows may be in zone 1, all of the south facing electrochromic windowsmay be in zone 2, all of the west facing electrochromic windows may bein zone 3, and all of the north facing electrochromic windows may be inzone 4. As yet another example, east facing electrochromic windows onone floor could be divided into different zones. Any number of tintablewindows on the same side and/or different sides and/or different floorsof the building may be assigned to a zone.

In some embodiments, electrochromic windows in a zone may be controlledby the same window controller. In some other embodiments, electrochromicwindows in a zone may be controlled by different window controllers, butthe window controllers may all receive the same output signals fromsensors and use the same function or lookup table to determine the levelof tint for the windows in a zone.

In some embodiments, electrochromic windows in a zone may be controlledby a window controller or controllers that receive an output signal froma transmissivity sensor. In some embodiments, the transmissivity sensormay be mounted proximate the windows in a zone. For example, thetransmissivity sensor may be mounted in or on a frame containing an IGU(e.g., mounted in or on a mullion, the horizontal sash of a frame)included in the zone. In some other embodiments, electrochromic windowsin a zone that includes the windows on a single side of the building maybe controlled by a window controller or controllers that receive anoutput signal from a transmissivity sensor.

In some embodiments, a sensor (e.g., photosensor) may provide an outputsignal to a window controller to control the electrochromic windows 505of a first zone (e.g., a master control zone). The window controller mayalso control the electrochromic windows 505 in a second zone (e.g., aslave control zone) in the same manner as the first zone. In some otherembodiments, another window controller may control the electrochromicwindows 505 in the second zone in the same manner as the first zone.

In some embodiments, a building manager, occupants of rooms in thesecond zone, or other person may manually instruct (using a tint orclear command or a command from a user console of a BMS, for example)the electrochromic windows in the second zone (i.e., the slave controlzone) to enter a tint level such as a colored state (level) or a clearstate. In some embodiments, when the tint level of the windows in thesecond zone is overridden with such a manual command, the electrochromicwindows in the first zone (i.e., the master control zone) remain undercontrol of the window controller receiving output from thetransmissivity sensor. The second zone may remain in a manual commandmode for a period of time and then revert back to be under control ofthe window controller receiving output from the transmissivity sensor.For example, the second zone may stay in a manual mode for one hourafter receiving an override command, and then may revert back to beunder control of the window controller receiving output from thetransmissivity sensor.

In some embodiments, a building manager, occupants of rooms in the firstzone, or other person may manually instruct (using a tint command or acommand from a user console of a BMS, for example) the windows in thefirst zone (i.e., the master control zone) to enter a tint level such asa colored state or a clear state. In some embodiments, when the tintlevel of the windows in the first zone is overridden with such a manualcommand, the electrochromic windows in the second zone (i.e., the slavecontrol zone) remain under control of the window controller receivingoutputs from the exterior sensor. The first zone may remain in a manualcommand mode for a period of time and then revert back to be undercontrol of window controller receiving output from the transmissivitysensor. For example, the first zone may stay in a manual mode for onehour after receiving an override command, and then may revert back to beunder control of the window controller receiving output from thetransmissivity sensor. In some other embodiments, the electrochromicwindows in the second zone may remain in the tint level that they are inwhen the manual override for the first zone is received. The first zonemay remain in a manual command mode for a period of time and then boththe first zone and the second zone may revert back to be under controlof the window controller receiving output from the transmissivitysensor.

Any of the methods described herein of control of a tintable window,regardless of whether the window controller is a standalone windowcontroller or is interfaced with a building network, may be used controlthe tint of a tintable window.

Wireless or Wired Communication

In some embodiments, window controllers described herein includecomponents for wired or wireless communication between the windowcontroller, sensors, and separate communication nodes. Wireless or wiredcommunications may be accomplished with a communication interface thatinterfaces directly with the window controller. Such interface could benative to the microprocessor or provided via additional circuitryenabling these functions.

A separate communication node for wireless communications can be, forexample, another wireless window controller, an end, intermediate, ormaster window controller, a remote control device, or a BMS. Wirelesscommunication is used in the window controller for at least one of thefollowing operations: programming and/or operating the electrochromicwindow 505, collecting data from the EC window 505 from the varioussensors and protocols described herein, and using the electrochromicwindow 505 as a relay point for wireless communication. Data collectedfrom electrochromic windows 505 also may include count data such asnumber of times an EC device has been activated, efficiency of the ECdevice over time, and the like. These wireless communication features isdescribed in more detail below.

In one embodiment, wireless communication is used to operate theassociated electrochromic windows 505, for example, via an infrared(IR), and/or radio frequency (RF) signal. In certain embodiments, thecontroller will include a wireless protocol chip, such as Bluetooth,EnOcean, WiFi, Zigbee, and the like. Window controllers may also havewireless communication via a network. Input to the window controller canbe manually input by an end user at a wall switch, either directly orvia wireless communication, or the input can be from a BMS of a buildingof which the electrochromic window is a component.

In one embodiment, when the window controller is part of a distributednetwork of controllers, wireless communication is used to transfer datato and from each of a plurality of electrochromic windows via thedistributed network of controllers, each having wireless communicationcomponents.

In some embodiments, more than one mode of wireless communication isused in the window controller distributed network. For example, a masterwindow controller may communicate wirelessly to intermediate controllersvia WiFi or Zigbee, while the intermediate controllers communicate withend controllers via Bluetooth, Zigbee, EnOcean, or other protocol. Inanother example, window controllers have redundant wirelesscommunication systems for flexibility in end user choices for wirelesscommunication.

Wireless communication between, for example, master and/or intermediatewindow controllers and end window controllers offers the advantage ofobviating the installation of hard communication lines. This is alsotrue for wireless communication between window controllers and BMS. Inone aspect, wireless communication in these roles is useful for datatransfer to and from electrochromic windows for operating the window andproviding data to, for example, a BMS for optimizing the environment andenergy savings in a building. Window location data as well as feedbackfrom sensors are synergized for such optimization. For example, granularlevel (window-by-window) microclimate information is fed to a BMS inorder to optimize the building's various environments.

D. Another Example of Predictive Control Logic

FIG. 25 is a block diagram depicting predictive control logic for amethod of controlling the tint level of one or more tintable windows(e.g., electrochromic windows) in different zones of a building,according to embodiments. This logic makes predictive determinations ata time in the future that accounts for the transition time of the ECdevices in the tintable windows. In the illustrated example, a portionof the predictive control logic is performed by window controller 1410,another portion is performed by network controller 1408, and the logicin Module 1 1406 is performed by a separate component from the windowcontroller 1410 and network controller 1408. Alternatively, Module 11406 may be separate logic that may or may not be loaded onto the windowcontroller 1410.

In FIG. 25, the portions of the predictive control logic employed bywindow controller 1410 and Module 1 1406 are managed by BMS 1407. BMS1407 may be similar to BMS 1100 described with respect to FIG. 15. BMS1407 is in electronic communication with window controller 1410 througha BACnet Interface 1408. In other embodiments, other communicationsprotocol may be used. Although not shown in FIG. 25, Module 1 1406 isalso in communication with BMS 1407 through BACnet Interface 1408. Inother embodiments, the predictive control logic depicted in FIG. 25 mayoperate independently of a BMS.

Network controller 1408 receives sensor readings from one or moresensors (e.g., an outside light sensor) and may also convert the sensorreading into W/m². The network controller 1408 is in electroniccommunication with the window controller 1410 via either CANbus orCANOpen protocol. The network controller 1408 communicates the convertedsensor readings to the window controller 1410.

In FIG. 25, the portion of the predictive control logic employed bywindow controller 1410 includes a master scheduler 1502. The masterscheduler 1502 includes logic that allows a user (e.g., buildingadministrator) to prepare a schedule that can use different types ofcontrol programs at different times of day and/or dates. Each of thecontrol programs includes logic for determining a tint level based on ormore independent variables. One type of control program is simply a purestate. A pure state refers to particular level of tint (e.g.,transmissivity=40%) that is fixed during a certain time period,regardless of other conditions. For example, the building manager mayspecify that the windows are clear after 3 PM every day. As anotherexample, building manager may specify a pure state for the time periodbetween the hours of 8 PM to 6 AM every day. At other times of day, adifferent type of control program may be employed, for example, oneemploying a much greater level of sophistication. One type of controlprogram offering a high level of sophistication. For example, a highlysophisticated control program of this type includes predictive controllogic described in reference to FIG. 25 and may include theimplementation of one or more of the logic Modules A, B, and C of Module1 1406. As another example, another highly sophisticated control programof this type includes predictive control logic described in reference toFIG. 25 and may include the implementation of one or more of the logicModules A, B, and C of Module 1 1406 and Module D described later inthis Section VII. As another example, another highly sophisticatedcontrol program of this type is the predictive control logic describedin reference to FIG. 17 and includes full multi-module implementation oflogic Modules A, B, and C described in reference to FIGS. 18, 19, and22. In this example, the predictive control logic uses sensor feedbackin Module C and solar information in Modules A and B. Another example ofa highly sophisticated control program is the predictive control logicdescribed in reference to FIG. 18 with partial logic moduleimplementation of one or two of the logic Modules A, B, and C describedin reference to FIGS. 18, 19, and 22. Another type of control program isa threshold control program that relies on feedback from one or moresensors (e.g., photosensors) and adjusts the tint level accordinglywithout regard to solar position. One of the technical advantages ofusing master scheduler 1502 is that the user can select and schedule thecontrol program (method) being used to determine the tint level.

Master scheduler 1502 runs the control programs in the scheduleaccording to time in terms of the date and time of day based on a24-hour day. Master scheduler 1502 may determine the date in terms of acalendar date and/or the day of the week based on a 7-day week with fiveweekdays (Monday through Friday) and two weekend days (Saturday andSunday). Master scheduler 1502 may also determine whether certain daysare holidays. Master scheduler 1502 may automatically adjust the time ofday for daylight savings time based on the location of the tintablewindows, which is determined by site data 1506.

In one embodiment, master scheduler 1502 may use a separate holidayschedule. The user may have determined which control program(s) to useduring the holiday schedule. The user may determine which days will beincluded in the holiday schedule. Master scheduler 1502 may copy thebasic schedule set up by the user and allow the user to set up theirmodifications for the holidays in the holiday schedule.

When preparing the schedule employed by master scheduler 1502, the usermay select the zone or zones (Zone Selection) of the building where theselected program(s) will be employed. Each zone includes one or moretintable windows. In some cases, a zone may be an area associated with aspace type (e.g., offices having a desk at a particular position,conference rooms, etc.) or may be associated with multiple space types.For example, the user may select Zone 1 having offices to: 1) Mondaythrough Friday: heat up at 8 am in morning to 70 degrees and turn on airconditioning to at 3 pm in afternoon to keep temperature in offices to80 degrees, and then turn off all air conditioning, and heat at 5 pmduring weekdays, and 2) (Saturday and Sunday) turn off heat and airconditioning. As another example, the user may set Zone 2 having aconference room to run the predictive control logic of FIG. 25 includingfull-module implementation of Module 1 using all of the logic Module A,B, and C. In another example, the user may select a Zone 1 havingconference rooms to run Module 1 from 8 AM to 3 PM and a thresholdprogram or pure state after 3 PM. In other cases, a zone may be theentire building or may be one or more windows in a building.

When preparing the schedule with programs that may use sensor input, theuser may also be able to select the sensor or sensors used in theprograms. For example, the user may select a sensor located on the roofor a sensor located near or at the tintable window. As another example,the user may select an ID value of a particular sensor.

The portion of the predictive control logic employed by windowcontroller 1410 also includes a user interface 1504 in electroniccommunication with master scheduler 1502. User interface 1504 is also incommunication with site data 1506, zone/group data 1508, and sense logic1516. The user may input their schedule information to prepare theschedule (generate a new schedule or modify an existing schedule) usinguser interface 1504. User interface 1504 may include an input devicesuch as, for example, a keypad, touchpad, keyboard, etc. User interface1504 may also include a display to output information about the scheduleand provide selectable options for setting up the schedule. Userinterface 1504 is in electronic communication with a processor (e.g.,microprocessor), which is in electronic communication with a computerreadable medium (CRM). Both the processor and CRM are components of thewindow controller 1410. The logic in master scheduler 1502 and othercomponents of the predictive control logic may be stored on the computerreadable medium of window controller 1410.

The user may enter their site data 1506 and zone/group data 1508 usinguser interface 1504. Site data 1506 includes the latitude, longitude,and GMT Offset for the location of the building. Zone/group dataincludes the position, dimension (e.g., window width, window height,sill width, etc.), orientation (e.g., window tilt), external shading(e.g., overhang depth, overhang location above window, left/right fin toside dimension, left/right fin depth, etc.), datum glass SHGC, andoccupancy lookup table for the one or more tintable windows in each zoneof the building. In FIG. 25, site data 1506 and zone/group data 1508 isstatic information (i.e. information that is not changed by componentsof the predictive control logic). In other embodiments, this data may begenerated on the fly. Site data 1506 and zone/group data 1508 may bestored on a computer readable medium of the window controller 1410.

When preparing (or modifying) the schedule, the user selects the controlprogram that master scheduler 1502 will run at different time periods ineach of the zones of a building. In some cases, the user may be able toselect from multiple control programs. In one such case, the user mayprepare a schedule by selecting a control program from a list of allcontrol programs (e.g., menu) displayed on user interface 1405. In othercases, the user may have limited options available to them from a listof all control programs. For example, the user may have only paid forthe use of two control programs. In this example, the user would only beable to select one of the two control programs paid for by the user.

Returning to FIG. 25, the portion of the predictive control logicemployed by window controller 1410 also includes time of day (lookahead) logic 1510. Time of day (look ahead) logic 1510 determines a timein the future used by predictive control logic to make its predictivedeterminations. This time in the future accounts for time needed totransition the tint level of the EC devices 400 in the tintable windows.By using a time that accounts for transition time, the predictivecontrol logic can predict a tint level appropriate for the future timeat which time the EC devices 400 will have had the time to transition tothe tint level after receiving the control signal. Time of day portion1510 may estimate the transition time of EC device(s) in arepresentative window based on information about the representativewindow (e.g., window dimension, etc.) from the Zone/Group Data. Time ofday logic 1510 may then determine the future time based on thetransition time and the current time. For example, the future time maybe equal to or greater than the current time added to the transitiontime.

The Zone/Group Data includes information about the representative windowof each zone. In one case, the representative window may be one of thewindows in the zone. In another case, the representative window may be awindow having average properties (e.g., average dimensions) based onaveraging all the properties from all the windows in that zone.

The predictive control logic employed by window controller 1410 alsoincludes a solar position calculator 1512. Solar position calculator1512 includes logic that determines the position of the sun, sun azimuthand sun altitude, at an instance in time. In FIG. 25, solar positioncalculator 1512 makes its determinations based on a future instance intime received from time of day logic 1510. Solar position calculator1512 is in communication with time of day portion 1510 and site data1506 to receive the future time, latitude and longitude coordinates ofthe building, and other information that may be needed to make itscalculation(s), such as the solar position calculation. Solar positioncalculator 1512 may also perform one or more determinations based on thecalculated solar position. In one embodiment, solar position calculator1512 may calculate clear sky irradiance or make other determinationsfrom Modules A, B, and C of Module 1 1406.

The control logic employed by window controller 1410 also includesschedule logic 1518, which is in communication with the sense logic1516, the user interface 1405, the solar position calculator 1512, andModule 1 1406. The schedule logic 1518 includes logic that determineswhether to use the tint level passing through the intelligence logic1520 from Module 1 1406 or use another tint level based on otherconsiderations. For example, as sunrise and sunset times changethroughout the year, the user may not want to reprogram the schedule toaccount for these changes. The schedule logic 1518 may use the sunriseand sunset times from the solar position calculator 1512 to set anappropriate tint level before sunrise and after sunset without requiringthe user to reprogram the schedule for these changing times. Forexample, the schedule logic 1508 may determine that according to thesunrise time received from the solar position calculator 1512 the sunhas not risen and that a pre-sunrise tint level should be used insteadof the tint level passed from Module 1 1406. The tint level determinedby the schedule logic 1518 is passed to sense logic 1516.

Sense logic 1516 is in communication with override logic 1514, schedulelogic 1518, and user interface 1405. Sense logic 1516 includes logicthat determines whether to use the tint level passed from schedule logic1516 or use another tint level based on the sensor data received throughthe BACnet interface 1408 from one or more sensors. Using the example inthe paragraph above, if schedule logic 1518 determines that it the sunhas not risen and passed a pre-sunrise tint level and the sensor datashows that the sun has actually risen, then sense logic 1516 would usethe tint level passed from Module 1 1406 through schedule logic 1518.The tint level determined by sense logic 1516 is passed to overridelogic 1514.

BMS 1407 and network controller 1408 are also in electroniccommunication with a demand response (e.g., utility company) to receivesignals communicating the need for a high demand (or peak load)override. In response to receiving these signals from the demandresponse, BMS 1407 and/or network controller 1408 may send instructionsthrough BACnet Interface 1408 to override logic 1514 that will processthe override information from the demand response. Override logic 1514is in communication with BMS 1407 and network controller 1408 throughthe BACnet Interface 1408, and also in communication with sense logic1516.

Override logic 1514 allows for certain types of overrides to disengagepredictive control logic and use an override tint level based on anotherconsideration. Some examples of types of overrides that may disengagepredictive control logic include a high demand (or peak load) override,manual override, vacant room override, etc. A high demand (or peak load)override defines a tint level from the demand response. For a manualoverride, an end user may enter the override value at a wall switcheither manually or through a remote device. A vacant room overridedefines an override value based on a vacant room (i.e. no occupant inthe room). In this case, the sense logic 1516 may receive sensor datafrom a sensor (e.g., motion sensor) indicating that the room is vacantand sense logic 1516 may determine an override value and relay theoverride value to override logic 1514. The override logic 1514 canreceive an override value and determine whether to use the overridevalue or use another value, such as another override value received froma source having higher priority (i.e., demand response). In some cases,the override logic 1514 may operate by steps similar to the overridesteps 630, 640, and 650 described with respect to FIG. 17.

The control logic employed by window controller 1410 also includesintelligence logic 1520 that can shut off one or more of Modules A 1550,B 1558 and C 1560. In one case, the intelligence logic 1520 may be usedto shut off one or more Modules where the user has not paid for thoseModules. Intelligence logic 1520 may prevent the use of certain moresophisticated features such as the penetration calculation made inModule A. In such cases, a basic logic is used that “short-circuits” thesolar calculator information and uses it to calculate tint levels,possibly with the assistance of one or more sensors. This tint levelfrom the basic logic is communicated to schedule logic 1518.

Intelligence logic 1520 can shut off one or more of the Modules (ModuleA 1550, Module B 1558 and Module C 1560) by diverting certaincommunications between the window controller 1410 and Module 1 1406. Forexample, the communication between the solar position calculator 1512and Module A 1550 goes through intelligence logic 1520 and can bediverted to schedule logic 1518 by intelligence logic 1520 to shut offModule A 1550, Module B 1558 and Module C 1560. As another example, thecommunication of tint level from Module A at 1552 to the Clear SkyIrradiance calculations at 1554 goes through intelligence logic 1520 andcan be diverted instead to schedule logic 1518 to shut off Module B 1558and Module C 1560. In yet another example, the communication of tintlevel from Module B at 1558 to Module C 1560 goes through intelligencelogic 1520 and can be diverted to schedule logic 1518 to shut off ModuleC 1560.

Module 1 1406 includes logic that determines and returns a tint level tothe schedule logic 1518 of window controller 1410. The logic predicts atint level that would be appropriate for the future time provided by thetime of day portion 1510. The tint level is determined for arepresentative tintable window associated with each of the zones in theschedule.

In FIG. 25, Module 1 1406 includes Module A 1550, Module B 1558 andModule C 1560, which may have some steps that are similar in somerespects to the steps performed in Modules A, B, and C as described withrespect to FIGS. 18, 19, 22 and 23. In another embodiment, Module 1 1406may be comprised of Modules A, B, and C as described with respect toFIGS. 18, 19, 20 and 23. In yet another embodiment, Module 1 1406 may becomprised of Modules A, B, and C described with respect to FIG. 24.

In FIG. 25, Module A 1550 determines the penetration depth through therepresentative tintable window. The penetration depth predicted byModule A 1550 is at the future time. Module A 1550 calculates thepenetration depth based on the determined position of the sun (i.e. sunazimuth and sun altitude) received from the solar position calculator1512 and based on the position of the representative tintable window,acceptance angle, dimensions of the window, orientation of the window(i.e. direction facing), and the details of any exterior shadingretrieved from the zone/group data 1508.

Module A 1550 then determines the tint level that will provide occupantcomfort for the calculated penetration depth. Module A 1550 uses theoccupancy lookup table retrieved from the zone/group data 1508 todetermine the desired tint level for the space type associated with therepresentative tintable window, for the calculated penetration depth,and for the acceptance angle of the window. Module A 1550 outputs a tintlevel at step 1552.

The maximum clear sky irradiance incident the representative tintablewindow is predicted for all times in the logic 1554. The clear skyirradiance at the future time is also predicted based on the latitudeand longitude coordinates of the building and the representative windoworientation (i.e. direction the window is facing) from the site data1506 and the zone/group data 1508. These clear sky irradiancecalculations can be performed by the sun position calculator 1512 inother embodiments.

Module B 1556 then calculates new tint levels by incrementallyincreasing the tint level. At each of these incremental steps, theInside Irradiance in the room based on the new tint level is determinedusing the equation: Inside Irradiance=Tint level SHGC×Clear SkyIrradiance. Module B selects the tint level where Inside Irradiance isless than or equal to Datum Inside Irradiance (Datum SHGC×Max. Clear skyIrradiance) and the tint level is not lighter than Tint Level from A.Module B 1556 outputs the selected tint level from B. From the Tintlevel from B, logic 1558 calculates the outside irradiance and thecalculated skylight irradiance.

Module C 1560 makes a determination of whether a sensor reading ofirradiance is less than the clear sky irradiance. If the determinationresult is YES, then the tint level being calculated is madeincrementally lighter (clearer) until the value matches or is less thana tint level calculated as Sensor Reading×Tint Level SHGC, but not toexceed datum inside Irradiance from B. If the determination result isNO, then the tint level being calculated is made darker in incrementalsteps as done in Module B 1556. Module C outputs the tint level. Logic1562 determines that the tint level from Module C is the final tintlevel and returns this final tint level (Tint level from Module C) tothe schedule logic 1518 of the window controller 1410.

In one aspect, Module 1 1406 may also include a fourth Module D that canpredict the effects of the surrounding environment on the intensity anddirection of sunlight through the tintable windows in the zone. Forexample, a neighboring building or other structure may shade thebuilding and block some light from passing through the windows. Asanother example, reflective surfaces (e.g., surfaces having snow, water,etc.) from a neighboring building or other surfaces in the environmentsurrounding the building may reflect light into the tintable windows.This reflected light can increase the intensity of light into thetintable windows and cause glare in the occupant space. Depending on thevalues of the intensity and direction of sunlight predicted by Module D,Module D may modify the tint level determined from Modules A, B, and Cor may modify certain determinations from Modules A, B, and C such as,for example, the penetration depth calculation or the acceptance angleof the representative window in the Zone/Group data.

In some cases, a site study may be conducted to determine theenvironment surrounding the building and/or one or more sensors may beused to determine the effects of the surrounding environment.Information from the site study may be static information based onpredicting the reflectance and shading (surrounding) effects for a timeperiod (e.g., a year), or may be dynamic information that can be updatedon a periodic basis or other timed basis. In one case, Module D may usethe site study to modify the standard acceptance angle and associated θ₁and θ₂ of the representative window of each zone retrieved from theZone/group data. Module D may communicate this modified informationregarding the representative windows other modules of the predictivecontrol logic. The one or more sensors employed by Module D to determinethe effects of the surrounding environment may be the same sensors usedby other modules (e.g., by Module C) or may be different sensors. Thesesensors may be specifically designed to determine the effects of thesurrounding environment for Module D.

To operate the predictive control logic shown in FIG. 25, the user firstprepares a schedule with details of the times and dates, zones, sensors,and programs used. Alternatively, a default schedule may be provided.Once the schedule is in place (stored), at certain time intervals (every1 minute, 5 minutes, 10 minutes, etc.) the time of day portion 1510determines a future time of day based on the current time and thetransition time of the EC device(s) 400 in the representative window oreach zone in the schedule. Using the zone/group data 1508 and site data1506, the solar position calculator 1512 determines the solar positionat the future (look ahead) time for each representative window of eachzone in the schedule. Based on the schedule prepared by the user, theintelligence logic 1520 is used to determine which program to employ foreach zone in the schedule. For each zone, the scheduled program isemployed and predicts an appropriate tint level for that future time. Ifthere is an override in place, an override value will be used. If thereis no override in place, then the tint level determined by the programwill be used. For each zone, the window controller 1410 will sendcontrol signals with the zone-specific tint level determined by thescheduled program to the associated EC device(s) 400 to transition thetint level of the tintable window(s) in that zone by the future time.

E. Filter(s) for Making Tinting Decisions Based on Rapidly ChangingConditions

In some systems, once a decision is made to tint a tintable window to aparticular end state, the window is committed to complete thattransition until reaching the end state. Such systems cannot adjust thefinal tint state during transition, and can only wait until transitionis complete. If an unsuitable end tint state is selected by thesesystems, the window is committed to this unsuitable tint level duringthe transition cycle and additionally any time that it takes totransition the window to a more appropriate tint level. Since tint/cleartimes take 5 to 30 minutes, for example, an unsuitable selection couldtie up a window in an inappropriate tint level for a substantial periodof time which could make conditions uncomfortable for the occupant.

Rapidly changing conditions (e.g., weather change such as intermittentclouds on a sunny day, a fog bank moving in or out, fog burning off tosunshine, etc.) combined with long transition times can cause controlmethods to “bounce” between end tint states. In addition, such controlmethods can decide on an end tint state based on a condition thatchanges immediately after the method commits to the transition, in whichcase the window is locked into an unsuitable tint level until thetransition is complete. For example, consider a mostly sunny day withdappled clouds. A control method may react to a drop in illuminationvalues when a cloud passes by and when the values rebound, glareconditions could exist. Even though the cloud passes by quickly, thewindow is committed to transitioning to the inappropriately low end tintstate for at least the duration of the transition cycle. During thistime, solar radiation enters the room which could also make ituncomfortably warm for the occupant.

An example of a rapidly changing weather condition is a foggy morningthat breaks into sunshine. Certain systems would determine a low tintlevel at the beginning of the day based on the low illumination readingsduring the morning fog. This low tint level would be inappropriately lowduring the period when the weather quickly transitions to clear skyafter the fog burns off. In this example, a more appropriate higher tintlevel for the clear sky may not be determined for a substantial periodof time (e.g., 35-45 minutes). Another example of a rapidly changingcondition is the onset of a reflection from an object such as, forexample, a parked car or an adjacent building's window.

Certain embodiments described herein include window control methods thatuse multiple filters to make tinting decisions that address rapidlychanging conditions. In certain cases, these filters can be used todetermine a more appropriate end tint state during a current transitioncycle to adjust the tint level of the window to a level appropriate forcurrent conditions. One type of filter is a box car filter (sometimescalled a sliding window filter), which employs multiple sensor readingsof illumination values running in time. A box car value is a calculatedcentral tendency (e.g., mean, average, or median) of a number, n, ofcontiguous sensor samples (readings of illumination values over time).Typically, the sensor samples are measurements of external radiation(e.g., by a sensor located on the outside of a building). A singlesensor can be used to take sensor samples for multiple windows such aswindows in a particular zone of a building. The sensor readingsgenerally take readings on a periodic basis at a uniform frequency(sampling rate). For example, the sensor may take samples at a rate inthe range of about one sample every 30 seconds to one sample everytwenty minutes. In one embodiment, a sensor takes samples at a rate ofone sample every minute. In some cases, one or more timers may also beused to maintain the tint at a current setting determined using a boxcar value.

In certain aspects, control methods use a short box car and one or morelong box cars (filters) to make tinting decisions. A short box car(e.g., one that employs sample values taken over 10 minutes, 20 minutes,5 minutes, etc.) is based on a smaller number of sensor samples (e.g.,n=1, 2, 3, . . . 10, etc.) relative to the larger number of sensorsamples (e.g., n=10, 20, 30, 40, etc.) in a long box car (e.g., one thatemploys sample values taken over 1 hour, 2 hours, etc.). In one case, ashort box car value is a median value of sensor samples and a long boxcar value is an average value of sensor samples. Since a short box carvalue is based on a smaller number of sensor samples, short box carvalues more closely follow the sensor readings than long box car values.Thus, short box car values respond to rapidly changing conditions morequickly and to a greater degree than the long box car values. Althoughboth the calculated short and long box car values lag behind the sensorreadings, the short box car will lag behind to a lesser extent than thelong box car.

Short box cars react more quickly than long box cars to currentconditions. A long box car filter smoothes the window controllerresponse to frequent short duration weather fluctuations, while a shortbox car does not smooth so well but responds better to rapid andsignificant weather changes. In the case of a passing cloud, a controlalgorithm using the long box car illumination value will not reactquickly to the current passing cloud condition. In this case, the longbox car illumination value should be used in tinting decisions todetermine an appropriate high tint level. In the case of fog burningoff, it may be more appropriate to use the short term box carillumination value in tinting decisions. In this case, the short termbox car reacts more quickly to the new sunny condition after the fogburns off. By using the short term box car value to make tintingdecisions, the tintable window quickly adjusts to the sunny conditionand keeps the occupant comfortable as the fog rapidly burns off.

In certain aspects, control methods evaluate the difference between theshort and long term box car values to determine which illumination valueto use in tinting decisions. When the difference (short term value minuslong term value) is positive and exceeds a first (positive) threshold(e.g., 20 W/m²), the value of the short term boxcar is used to calculatea tint value. Note that a positive value corresponds to a transition tobrightening (a greater radiant intensity outside the window). In someimplementations, a first timer is set when the positive threshold isexceeded, in which case a currently calculated tint value is maintainedfor a prescribed amount of time of the first timer. Using the firsttimer will favor glare control by holding the window in a more tintedstate and preventing too many transitions that may annoy an occupant. Onthe other hand, when the difference between the short car and long carvalues is less than the threshold (or negative), the long term box valueis used to calculate the next tint state. And if the difference isnegative and greater than a second (negative) threshold, then a secondtimer may be set. The positive threshold values may be in the range ofabout 1 Watts/m² to 200 Watts/m² and the negative threshold values maybe in the range of about −200 Watts/m² to −1 Watts/m². The calculatedtint value based on the long box car is maintained during a prescribedamount of the time of the second timer. Once the control methoddetermines which box car value to use, the method will make tintingdecisions based on whether the box car value is above an upper limit,below a lower limit, or between the upper and lower limits. If above theupper limit, Modules A and B (or just B in some cases) are used todetermine tint change. If above the lower limit and below the upperlimit, Modules A, B, and C (or just B and C in some cases) are used todetermine tint change. If below the lower limit, a defined tint level isapplied (e.g., nominally clear). In certain cases, the lower limit maybe in the range of 5 Watts/m² to 200 Watts/m² and the upper limit may bein the range of 50 Watts/m² to 400 Watts/m².

FIG. 26A is a flowchart 3600 showing a particular implementation of thecontrol logic shown in FIG. 17. At step 3610, the control methoddetermines whether the time is between sunrise and sunset. If it iseither before sunrise or after sunset at step 3610, the control methodclears the tint in the window and proceeds to step 3620 to determinewhether there is an override. If it is determined to be between sunriseand sunset at step 3610, the control method determines whether the sunazimuth is between critical angles (step 3620). FIG. 27B depicts a roomhaving a desk and critical angles of the tintable window in the room. Ifthe sun azimuth is within the critical angles, sun is shining onto anoccupant sitting at the desk. In FIG. 27B, the sun azimuth is shownoutside the illustrated critical angles. Returning to the flowchart inFIG. 26A, if it is determined at step 3620 that the sun azimuth outsidethe critical angles, Module A is not used and Module B is used at step3800 is used. If it is determined that the sun azimuth between thecritical angles, Module A is used at step 3700 and Module B is used atstep 3800. At step 3820, the control method determines whether thesensor value is below a threshold 1 or above a threshold 2. If thesensor value is below threshold 1 or above threshold 2, Module C (step3900) is not used. If the sensor value is above threshold 1 and belowthreshold 2, Module C is used. In either case, the control methodproceeds to step 3920 to determine whether there is an override inplace.

FIG. 26B is a graph of illumination readings from a sensor taken duringa day that is cloudy (e.g., foggy) early in the day and sunny (clearsky) later in the day. As shown, the values of the illumination readingsare below a lower limit before 7 a.m., rise above the lower limit andthen above the upper limit, and then as the clouds burn off after 10a.m. the illumination readings become much higher later in the day.While the sensor reads illumination levels below a lower limit (e.g., 10Watts/m²) before 7 a.m., the amount of radiation through the tintablewindow is not significant enough to affect occupant comfort. In thiscase, a re-evaluation of tint level does not need to be made and adefined tint level (e.g., maximum window transmissivity) is applied.While the sensor reads between the lower and upper limit (e.g., 100Watts/m²) after 7 a.m. and before 10 a.m., modules A, B, and C will beused to calculate an end tint state. While the sensor reads above theupper limit (e.g., 100 Watts/m2) after 10 a.m., modules A and B will beused to calculate an end tint state.

FIG. 27A is a flowchart 4000 of a control method that uses short andlong box car values to make tinting decisions, according to someembodiments. Although the flowchart is shown using one short term boxcar value and one long term box car value, other embodiments may includeuse more box car values such as, for example, a second long term box carvalue. The illustrated control method periodically receives sensorreadings of illumination values and updates the long term and short termbox car values. If a timer is set, then current tint level will bemaintained at the current tint setting. The method evaluates thedifference between the short and long term box car values to determinewhich box car value to use as an illumination value in tintingdecisions. If the difference between the values is greater than athreshold value, the short term box car value is used and a timer is setduring which the current tint setting will be maintained. If thedifference between the values is lower than the threshold value, thelong term box car value is used and a different timer may be set(depending on the magnitude of the difference). Using the previouslydetermined box car value as the illumination level, the methoddetermines whether the illumination value is below a lower tint leveland if so, a defined tint level is applied (e.g., nominally clear). Ifthe illumination value is above the upper limit, the method determineswhether the sun is outside the critical angle. FIG. 24B depicts a roomhaving a desk and the critical angle of the room within which the sun isshining onto an occupant sitting at the desk. In the illustration, thesun is outside the critical angle. If the method determines that the sunis outside the critical angle, only Module B is used to determine tintlevel. If within the critical angle, Modules A and B are used todetermine tint level. If the illumination value is above the lower limitand below the upper limit, the method determines whether the sun isoutside the critical angle. If outside the critical angle, Modules B andC are used to determine tint level. If within the critical angle,Modules A, B, and C are used to determine tint level.

More specifically with reference back to FIG. 27A, sensor readings ofillumination values (e.g., external radiation readings) are sent by thesensor and received by the processor at step 4010. Generally, the sensortakes samples on a periodic basis at a uniform rate (e.g., one sampletaken every minute). At step 4012, the long term and short term box carillumination values are updated with the received sensor readings. Inother words, the oldest values in the box car filters are replaced withthe newest value and new box car illumination values are calculated,usually as central tendencies of samples in the box cars. At step 4020,it is determined whether a timer is set. If a timer is set, then thecurrent tint setting is maintained at step 4022 and the process returnsto step 4010. In other words, the process does not calculate a new tintlevel. If a timer is not set, the magnitude and sign of the differencebetween the short term and long term box car illumination values (Δ) isdetermined at step 4030. That is, Δ=Short Term Box Car value−Long termBox Car value. At step 4040, it is determined whether Δ is positive andgreater than a first threshold value. If Δ is positive and greater thana first threshold value, then the illumination value for the system isset to short term box car illumination value and a first timer is set atstep 4042 and the method proceeds to step 4050. If Δ is not positive andgreater than the first threshold value, then the illumination value forthe system is set to the long term box car illumination value at step4044. At step 4046, it is determined whether Δ is more negative than asecond threshold value. If Δ is more negative than the second thresholdvalue, then a second timer is set at 4048, and the method proceeds tostep 4050. If not, the method directly proceeds to step 4050. At step4050, it is determined whether the set illumination value for the systemis less than a lower limit. If the set illumination value for the systemis less than the lower limit, a defined tint level (e.g., nominallyclear) is applied at step 4052 and the process returns to step 4010. Ifthe set illumination value for the system is greater than a lower limit,it is determined whether the set illumination value for the system isgreater than an upper limit at step 4060. If it is determined that theset illumination value for the system is greater than an upper limit,then it is determined whether the sun azimuth is outside the criticalangles at 4070. If the sun is not outside the critical angles, Modules Aand B are used to determine a final tint level applied to the tintablewindow and the process returns to step 4010. If the sun is outside thecritical angles, only Module B is used to determine the final tint stateat step 4074 and the process returns to step 4010. If it is determinedthat the set illumination value for the system is not greater than anupper limit at step 4060, then it is determined whether the sun isoutside the critical angle at 4080. If the sun is not outside thecritical angle, Modules A, B, and C are used to determine a final tintlevel at step 4082 applied to the tintable window and the processreturns to step 4010. If the sun is outside the critical angles, onlyModules B and C are used to determine the final tint level at step 4090applied to the tintable window and the process returns to step 4010.

FIG. 28A depicts two graphs associated with sensor readings during aregular day and the associated tint states determined by the controlmethod described with reference to FIG. 27A. The bottom graph showssensor readings at time, t, over the day. The bottom graph also includesa bell-shaped curve of clear sky illumination values over time, t, forreference purposes. The particular bell-shaped curve would be an exampleof values at a south facing window (because the bell is roughly centeredin the dawn to dusk time scale) with critical angles of 90 (East) to 270(West). The bottom graph also includes a curve of sensor readings takenover time, t during a day when the weather periodically deviates fromclear sky. The sensor readings are typically measurements of externalradiation. The bottom graph also includes curves of updated short boxcar values and long box car values calculated at time, t. These valuesare usually calculated as central tendencies of the samples in the boxcars updated at time, t. The curve of sensor readings also shows dropsin illumination at the passing of four clouds 1, 2, 3, and 4, and thenreturning to sunshine after each of the clouds pass. The short box carcurve follows the sensor reading curve and reacts quickly to the dropsin illumination from the four clouds. The long box car values lag behindthe sensor readings and do not react to the same extent to the drops inillumination from the clouds. The top graph shows the tint statetransmission (T_(vis)) through the tintable window calculated by thecontrol method at time, t. Until just before event 0, the positivedifference between the short term box car value and the long term boxcar value is less than a (positive) threshold value (e.g., 20 Watts/m²),and the illumination value is set to the updated long box car value.Since the illumination value is below the lower limit, a defined tintlevel (nominally clear state) associated with a T_(vis) of 60% isapplied. As shown, the control method applies T_(vis) of 60% until thepositive difference between the short term box car value and the longterm box car value is greater than a (positive) threshold value (e.g.,20 Watts/m²), and then the illumination value is set to the short boxcar value (event 0). At this time, Timer 1 is set and the tint statecalculated at event 0 is maintained until Timer 1 expires just aftercloud 1 passes. Since the illumination value (based on the short box carvalue) is greater than the lower limit and less than the high limit andthe sun is within the critical angles, Modules A, B, and C are used todetermine a tint level at event 0 corresponding to T_(vis) of 20%.Thereafter, the value of the short term box car passes the upper level,triggering a calculation based on Modules A and B only. No change intint level occurs since Timer 1 is set. Just after the time Cloud 1passes, Timer 1 expires. From this time until just before cloud 3, thepositive difference between the short term box car value and the longterm box car value is greater than the positive threshold value and theillumination value is set to the updated short term box car value.During this time, the illumination values (based on the updated shortterm box car values) remain above the upper limit and the sun remainswithin the critical angles, and so Modules A and B are again used todetermine a tint level and they calculate a tint level corresponding toT_(vis) of 4%. At Cloud 3, the long box car value is greater than theshort box car value and the difference is now negative and so theillumination value is set to the long box car value. Since thedifference is less negative than the (negative) threshold value, notimer is set. Since the illumination value is greater than the upperlimit and the sun is outside the critical angles, Modules A and B areagain used to determine tint level. At Cloud 4, the long box car valueis again greater than the short box car value, and the difference isless negative than the (negative) threshold value. At this time, theillumination value is set to the updated long box car value, but notimer is set. Since the illumination value is greater than the low limitand less than the high limit and the sun is outside the critical angles,Modules A, B, and C are used to determine a tint level and theycalculate a tint level corresponding to a T_(vis) of 40%.

FIG. 28B depicts two graphs associated with sensor readings during acloudy day with intermittent spikes and the associated tint statesdetermined by the control method described with reference to FIG. 27A.The bottom graph shows sensor readings at time, t, over the cloudy day.The bottom graph also includes a bell-shaped curve of clear skyillumination values over time, t, for reference purposes. The bottomgraph also includes curves of updated short box car values and long boxcar values calculated at time, t. The curve of sensor readings showsthat conditions are cloudy in the morning until point 3 when it becomessunny for a short period with two drops before becoming cloudy again.The top graph shows the tint state transmission T_(vis) through thetintable window calculated by the control method at time, t. Beforepoint 1, the positive difference between the short term box car valueand the long term box car value is less than the threshold value, andillumination value is set to the long box car value. Since theillumination value is below the lower limit, a defined tint level(nominally clear) associated with a of 60% is applied. At point 1, thedifference between the short term and long term box car values ispositive and less than a threshold value, and the illumination value isset to the updated long box car value. In this case, the illuminationvalue is between the lower and upper limit and it is early in the day sothat the sun is outside the critical angles so that Module A does notneed to be used to determine penetration depth. In this case, onlyModules B and C are used and they calculate the tint level at T_(vis) of40% to darken the window. At point 2, the difference between the shortterm and long term box car values is positive and less than a thresholdvalue, and the illumination value is set to the updated long box carvalue. At this point, it is still early in the day and the sun isoutside the critical angles. The illumination value is higher than itwas at point 1, but still between the upper and lower limit, and ModulesB and C determine a tint level at T_(vis) of 20% to darken the windowfurther. At point 3, the difference between the short term and long termbox car values is positive and greater than a threshold value, and sothe illumination value is set to the updated short box car value andTimer 1 is set. Since the illumination value is above the upper limitand the sun is within the critical angles, Modules A and B are used todetermine increase the tint to a tint level corresponding to T_(vis) of4%. During the timer's length, the tint state will be maintained. Justbefore point 4, Timer 1 expires. At point 4, the positive differencebetween the short term and long term box car values is greater than a(positive) threshold value, and the illumination value is set to theupdated short box car value. The illumination value is above the lowerlimit and the sun is outside the critical angles at this time of day sothat only Module B is used to determine a tint level corresponding toT_(vis) of 40%. At point 5, the positive difference between the shortterm and long term box car values is less than the threshold value, andthe illumination value is set to the updated long box car value. Notimer is set. At this point late in the day, the illumination value isbelow the lower limit and Modules B and C are used to determine a tintlevel corresponding to T_(vis) of 60%.

In some control methods, the long box car value is updated with sensorreadings and is never reset during the day. If sensor readings were tochange significantly during the day (e.g., when a storm front arrived),these long box car values would lag substantially behind the rapidchange in sensor readings and would not reflect the rapid change. Forexample, the long box car values are significantly higher than thesensor readings after a substantial drop in external illumination. Ifthese high long box car values are used to calculate a tint level, thewindows may be over-tinted until the long box cars had time to load withmore current sensor readings. In certain aspects, control methods resetthe long box car after a rapid change in illumination so that the longbox car can be loaded with more current sensor readings. FIGS. 29A-29Bare illustrations of control methods that reset loading of the long boxcar. In other aspects, control methods use a second long box car that isinitiated with a significant change in illumination condition. FIGS.30A-30B are illustrations of control methods that have a second long boxcar. In these cases, the control methods can use long box car valuesthat are closer to the current sensor readings and may avoid overtintingthe windows after a rapid drop in illumination.

FIG. 29A is a flowchart 5000 of a control method that resets loading ofa long box car, according to embodiments. The long box car is reset andstarts reloading current sensor readings after a rapid change in sensorreadings. The long box car is reset when the negative difference betweenthe short box car value and long box car value is greater than athreshold value. That is, a negative difference greater than thethreshold value indicates a rapid change in sensor readings. At the sametime, the control method starts a second timer. The control method usesthe reset long box car value to calculate tint level that will bemaintained during the second timer. Since the long box car startsreloads with new sensor readings when the conditions change, the longbox car value closely follows sensor readings for a time and the controlmethod will determine tint levels that closely correspond to the rapidlychanging sensor readings.

More specifically with reference back to FIG. 29A, sensor readings ofillumination values are sent by the sensor and received by the processorat step S010. At step S012, the long term and short term box carillumination values are updated with the received sensor readings. If itis determined at step S020 that a timer is set, then the current tintsetting is maintained (i.e. no calculation of a new tint level) at stepS022 and the process returns to step S010. If is determined that a timeris not set at step S020, then the magnitude and sign of the differencebetween the short term and long term box car illumination values (Δ) isdetermined at step S030. That is, Δ=Short Term Box Car value—Long TermBox Car value. If it is determined at step S030 that Δ is positive andgreater than a first threshold value, then the illumination value is setto the short term box car illumination value, a first timer is set atstep S042, and the method proceeds to step S050. If it is determined atstep S030 that Δ is positive and less than the threshold value or anegative value, then the illumination value is set to the long term boxcar illumination value at step S044. At step S046, it is determinedwhether Δ is more negative than a second threshold value. If Δ is morenegative than the second threshold value, then there has been asignificant drop in illumination. In this case, a second timer is setand the long box car is reset at step S048 to start loading again, andthe method proceeds to step S050. If Δ is not more negative than thesecond threshold value, the method directly proceeds to step S050. Atstep S050, it is determined whether the set illumination value is lessthan a lower limit. If less than the lower limit, a defined tint level(e.g., nominally clear) is applied at step S052 and the process returnsto step S010. If the set illumination value for the system is greaterthan a lower limit, it is determined whether the set illumination valuefor the system is greater than an upper limit at step S060. If it isdetermined that the set illumination value for the system is greaterthan an upper limit, then it is determined whether the sun azimuth isoutside the critical angles at 5070. If the sun is not outside thecritical angles, Modules A and B are used to determine a final tintlevel applied to the tintable window and the process returns to stepS010. If the sun is outside the critical angles, only Module B is usedto determine the final tint state at step S074 and the process returnsto step S010. If it is determined that the set illumination value forthe system is not greater than an upper limit at step S060, then it isdetermined whether the sun is outside the critical angle at 5080. If thesun is not outside the critical angle, Modules A, B, and C are used todetermine a final tint level at step S082 applied to the tintable windowand the process returns to step S010. If the sun is outside the criticalangles, only Modules B and C are used to determine the final tint levelat step S090 applied to the tintable window and the process returns tostep S010.

FIG. 29B illustrates a scenario of sensor readings and box car valuesduring time, t, during a portion of a day. This scenario assumes abright sunny day (500 W/m²) at noon and the box car curves are trackingtogether for the most part at this time, with calculations going onevery 5 minutes. At the first vertical black line (regular 5 mininterval calculations) there has been a slight drop in sensor readingsand the short term box car value is slightly higher than the long termbox car value, which lags behind the sensor readings. Since the negativedifference between the short term and long term values is below thethreshold value, the long term box car value is used to determine tintlevel. At the very next calculation, the sensor readings are showing alarge drop in external illumination (e.g., storm front arrived). Thenegative difference is greater than the threshold value and the controlmethod triggers a 1 hour timer (changing condition has caused thisevent, made delta sufficient to trigger the timer) and the long box caris reset. The control method sets the illumination value to the resetlong box car value to determine a tint level to use during the timerperiod. Since the long term box car value is above the upper limit andthe sun is within the critical angles, Modules A and B are used todetermine the tint level based on the reset long box car value. At theend of the second timer period, the negative difference between shortbox car and long box car values is less than the threshold value so thatthe illumination is set to the reset long term box car values.

At the end of the second timer period, if we were to simply use thelogic without resetting the long box car, the second timer would againbe implemented and the long box car values would be used during the timeperiod (as before). As you can see, this would be the wrong result, asthe actual sensor readings (and the short box car) data show it is adull day and the window doesn't need to be tinted according to the longbox car data (it's still way off from reality). In this scenario, a longterm box car is reset at the timer start period. In other words, oncethe timer is triggered, this simultaneously triggers resetting the longbox car to start loading with sensor data. Under this logic, at the endof the second timer, the short term box car's value is compared with thereset long box car and the delta now would more closely reflect actualsensor readings.

FIG. 30A is a flowchart 6000 of a control method that initiates a secondlong box car when there is a rapid change in sensor readings. The valuesof the newly-initiated second long box car closely track the sensorreadings during the rapid change. The first long box car lags behind thesensor readings.

With reference back to FIG. 30A, sensor readings of illumination valuesare sent by the sensor and received by the processor at step 6010. Atstep 6012, box car illumination values are updated with the receivedsensor readings. If it is determined at step 6020 that a timer is set,then the current tint setting is maintained (i.e. no calculation of newtint level) at step 6022 and the process returns to step 6010. If isdetermined that a timer is not set at step 6020, it is determinedwhether a second long box car has been initiated at step 6024. If asecond long box car is determined to be initiated at step 6024, Value 1is set to the greater of the short box car and the first long box carillumination values and Value 2 is set to the second long box carillumination value. If a second long box car has not been initiated,Value 1 is set to the short box car illumination value and Value 2 isset to the second long box car illumination value. At step 6030, themagnitude and sign of the difference between Value 1 and Value 2 (Δ) isdetermined. If it is determined at step 6030 that Δ is positive andgreater than a first threshold value, then at step 6042, theillumination value is set to Value 1 and a first timer is set, and thenthe method proceeds to step 6050. If it is determined at step 6030 thatΔ is positive and less than the threshold value or Δ is a negativevalue, then the illumination value is set to Value 2 at step 6044. Atstep 6046, it is determined whether Δ is more negative than a secondthreshold value. If Δ is more negative than the second threshold value,then there has been a significant drop in illumination. In this case, asecond timer is set, a second long box car is initiated, and theillumination value is set to the initial value of the second long boxcar at step 6048, and the method proceeds to step 6050. If Δ is not morenegative than the second threshold value, the method directly proceedsto step 6050. At step 6050, it is determined whether the setillumination value is less than a lower limit. If less than the lowerlimit, a defined tint level (e.g., nominally clear) is applied at step6052 and the process returns to step 6010. If the set illumination valuefor the system is greater than a lower limit, it is determined whetherthe set illumination value for the system is greater than an upper limitat step 6060. If it is determined that the set illumination value forthe system is greater than an upper limit, then it is determined whetherthe sun azimuth is outside the critical angles at 6070. If the sun isnot outside the critical angles, Modules A and B are used to determine afinal tint level applied to the tintable window and the process returnsto step 6010. If the sun is outside the critical angles, only Module Bis used to determine the final tint state at step 6074 and the processreturns to step 6010. If it is determined that the set illuminationvalue for the system is not greater than an upper limit at step 6060,then it is determined whether the sun is outside the critical angle at6080. If the sun is not outside the critical angle, Modules A, B, and Care used to determine a final tint level at step 6082 applied to thetintable window and the process returns to step 6010. If the sun isoutside the critical angles, only Modules B and C are used to determinethe final tint level at step 6090 applied to the tintable window and theprocess returns to step 6010.

FIG. 30B illustrates a scenario of sensor readings and box car valuesduring time, t, during a portion of a day. This scenario assumes abright sunny day (500 W/m²) at noon and the box car curves are trackingtogether for the most part at this time, with calculations going onevery 5 minutes. At the first vertical black line (regular 5 mininterval calculations) there has been a slight drop in sensor readingsand the short term box car value is slightly higher than the first longterm box car value, which lags behind the sensor readings. Since thenegative difference between the short and first long box car values isbelow the threshold value, the first long box car value is used todetermine tint level. At the very next calculation, the sensor readingsare showing a larger drop in external illumination. In this case, thenegative difference is greater than the threshold value and the controlmethod triggers a 1 hour timer (changing condition has caused thisevent, made delta sufficient to trigger the timer) and a second long boxcar is initiated. In addition, the illumination value is set to theinitial second long box car value. Since this initial second long termbox car value is above the upper limit and the sun is within thecritical angles, Modules A and B are used to determine the tint levelbased on the initial second long box car value. At the end of the secondtimer period, the first long box car value is greater than the short boxcar value and the positive difference between the second long box carvalue and first long box car value is below the first threshold value.The control method uses the first long box car illumination value todetermine a tint level that will be used during the first timer.

Modifications, additions, or omissions may be made to any of theabove-described predictive control logic, other control logic and theirassociated control methods (e.g., logic described with respect to FIG.25, logic described with respect to FIGS. 12, 13, 14, and 15, and logicdescribed with respect to FIG. 24) without departing from the scope ofthe disclosure. Any of the logic described above may include more,fewer, or other logic components without departing from the scope of thedisclosure. Additionally, the steps of the described logic may beperformed in any suitable order without departing from the scope of thedisclosure.

Also, modifications, additions, or omissions may be made to theabove-described systems or components of a system without departing fromthe scope of the disclosure. The components of the may be integrated orseparated according to particular needs. For example, the master networkcontroller 1403 and intermediate network controller 1405 may beintegrated into a single window controller. Moreover, the operations ofthe systems can be performed by more, fewer, or other components.Additionally, operations of the systems may be performed using anysuitable logic comprising software, hardware, other logic, or anysuitable combination of the preceding.

It should be understood that the present invention as described abovecan be implemented in the form of control logic using computer softwarein a modular or integrated manner. Based on the disclosure and teachingsprovided herein, a person of ordinary skill in the art will know andappreciate other ways and/or methods to implement the present inventionusing hardware and a combination of hardware and software.

Any of the software components or functions described in thisapplication, may be implemented as software code to be executed by aprocessor using any suitable computer language such as, for example,Java, C++ or Perl using, for example, conventional or object-orientedtechniques. The software code may be stored as a series of instructions,or commands on a computer readable medium, such as a random accessmemory (RAM), a read only memory (ROM), a magnetic medium such as ahard-drive or a floppy disk, or an optical medium such as a CD-ROM. Anysuch computer readable medium may reside on or within a singlecomputational apparatus, and may be present on or within differentcomputational apparatuses within a system or network.

Although the foregoing disclosed embodiments have been described in somedetail to facilitate understanding, the described embodiments are to beconsidered illustrative and not limiting. It will be apparent to one ofordinary skill in the art that certain changes and modifications can bepracticed within the scope of the appended claims.

One or more features from any embodiment may be combined with one ormore features of any other embodiment without departing from the scopeof the disclosure. Further, modifications, additions, or omissions maybe made to any embodiment without departing from the scope of thedisclosure. The components of any embodiment may be integrated orseparated according to particular needs without departing from the scopeof the disclosure.

What is claimed is:
 1. A combination sensor comprising: a set ofphysical sensors facing different directions proximate a structure, andconfigured to measure solar radiation in different directions; and avirtual facade-aligned sensor configured to determine a combi-sensorvalue at a facade of the structure based on solar radiation readingsfrom the set of physical sensors.
 2. The combination sensor of claim 1,wherein the combi-sensor value is determined by combining the solarradiation readings of the set of physical sensors, wherein thecombi-sensor value applies to the facade at any orientation.
 3. Thecombination sensor of claim 2, wherein the combi-sensor value is amaximum value of the solar radiation readings of the set of physicalsensors.
 4. The combination sensor of claim 2, wherein the combi-sensorvalue is an average value of the solar radiation readings of the set ofphysical sensors.
 5. The combination sensor of claim 2, wherein thecombi-sensor value is a sum of the solar radiation readings of the setof physical sensors.
 6. The combination sensor of claim 1, wherein thecombi-sensor value is an interpolated value from the solar radiationreadings of two sensors of the set of physical sensors that are closestto the facade.
 7. The combination sensor of claim 1, wherein thecombi-sensor value of the virtual facade-aligned sensor is determined byshifting in time a solar radiation value of one of the set of physicalsensors.
 8. The combination sensor of claim 1, wherein the set ofphysical sensors comprises four approximately orthogonally-directedsensors.
 9. The combination sensor of claim 8, wherein the fourapproximately orthogonally-directed sensors are directed to the North,East, South, and West.
 10. The combination sensor of claim 1, whereinthe set of physical sensors comprises three physical sensors.
 11. Thecombination sensor of claim 1, wherein the three physical sensors aredirected to face approximately W, E, and S.
 12. The combination sensorof claim 1, further comprising a mast mounted to the structure, whereinthe set of physical sensors is mounted to the mast in a ring sensorarrangement.
 13. The combination sensor of claim 12, wherein the set ofphysical sensors comprises twelve physical sensors equally spaced abouta central axis of the mast.
 14. The combination sensor of claim 13,wherein the physical sensors are equally spaced about a central axis ofthe mast.
 15. The combination sensor of claim 14, wherein the set ofphysical sensors comprises twelve physical sensors equally spaced aboutthe central axis of the mast.
 16. A method comprising: determining solarradiation readings taken by a set of physical sensors; and determining acombi-sensor value of a virtual facade-aligned sensor based on the solarradiation readings taken by the set of physical sensors.
 17. The methodof claim 16, wherein determining the combi-sensor value comprisescombining the solar radiation readings of the set of physical sensors,wherein the combi-sensor value applies to the facade at any orientation.18. The method of claim 17, wherein combining the solar radiationreadings comprises determining a maximum value of the solar radiationreadings of the set of physical sensors.
 19. The method of claim 17,wherein combining the solar radiation readings comprises averaging thesolar radiation readings of the set of physical sensors.
 20. The methodof claim 17, wherein combining the solar radiation readings comprisessumming the solar radiation readings of the set of physical sensors. 21.The method of claim 16, wherein determining the combi-sensor valuecomprises interpolating from the solar radiation readings of two sensorsof the set of physical sensors that are closest to the facade.
 22. Themethod of claim 21, further comprising: determining solar radiationreadings taken by the set of physical sensors taken for one or moreclear sky days; determining a degree of misalignment between a facade ofthe virtual facade-aligned sensor and each of the physical sensors; anddetermining the two closest physical sensors of the set of physicalsensors to the virtual facade-aligned sensor based on the determineddegree of misalignment of each of the physical sensors.